I found the information below to be the best info on grading I could find on the internet a few years ago, this is what I try to go by. I grade my records following the Goldmine grading system, except I use 'Excellent' for records that fall between 'Near Mint' and 'Very Good +' quality. For other items such as CD's and books, refer to the cover artwork grading for a general guide.

In Compiling this information the following people have participated with
vital information....

Susan Murray (NOD International Records) cyteen@ix.netcom.com
Fred Walker (Vinylonly) vinylonly@aol.com
Paula Major (Paula's House of Music) paula@houseofmusic.com
Tim Toms (Back-Trac Records) backtrac45@aol.com
And of course myself (Dennis Major)

A1: The Goldmine Grading System was 1st created in the early years of record collecting. These grades were established from various other resources pertaining to collecting (for example coin, book, comics, and card collecting). Goldmine Magazine first published a grading scale in 1974. It has undergone changes through out the years, yet has for the most part remained the same.
*** Remember! Two people may not come up with the same grade for the same record. One person may feel a record is MINT and another may say NM (Near Mint). After reading the next part of this answer, perhaps you will be able to identify each grade with out too much confusion, and allow yourself to grade more conservatively (fairly).

Grade Scale with definitions of each grade:

A2: Below is the grade scale and what you should look for when assessing a grade for each record you have.

*** Okay, but how can I honestly grade a record MINT??? *** MINT COVERS: Simply put, a mint cover should appear to have never had a record inside it. No wear to the corners or any marks on the face or back of the cover. EP jackets (for 7 inch extended plays) and 45 single picture sleeves also apply to this rule. The record inside can cause an impression (a round shape in the face of the cover/sleeve) Many dealers or sellers feel that the artwork (the ink) has to be worn or starting to rub off, before there is any ring wear. NOPE!! Mint means perfect and nothing else!

**NOTE: Anytime a person calls anything MINT you should expect a perfect, visually flawless item. We should actually use the term PERFECT rather than the term MINT. Probably no one would ever use this grade. PERFECT is to say that man (who is not perfect) can produce a perfect item. No way! MINT is already abused in the open market and many people would be disappointed when they find some flaw to cause it to be an overgrade. My feelings are NOTHING is perfect and to call anything MINT is purely "Hype".

***2ND SPECIAL NOTE: It has been brought to my attention that because stickers may involve promo and special track listings that were applied from the factory, it is still not a standard practice. Promo stickers and large white programming labels (on the bottom of the covers) are considered a turn off. Therefore even these stickers would lower the grade from a MINT status to perhaps only EX. Stickers that show special announcements, such as "Featuring the hit song...etc.", were not applied to all the commercial releases. Some earlier copies may not have the sticker since the song in question had not even charted yet. It was to advertise the whole LP and draw attention to the buyer. Some stickers are worth money! That means they actually have value. Most companies applied the stickers to the shrink-wrap and thus, one should save these items, but if applied to the covers, NM is the best way to grade these covers. If you wish to place value on the sticker (most are anywhere from 50 cents to $2.00) then do so but make mention of the sticker being on the cover to potential buyers! Many people want sticker free covers!

MINT VINYL: This should be very simple to define (said with tongue in cheek). A mint record should look perfect, as described earlier. Any defect from the factory pressing, such as bubbles or pits in the vinyl are not acceptable! Even if they do not cause any problem when played. It should, as we said, be a perfect pressing. Records were ALL packaged by hand and the simple placing of the record into a paper sleeve can caused minor scuffs. Probably very insignificant, but they are flaws never the less. For this reason, it is impossible to call a sealed record mint. Thus any sealed record that is sold, should be sold only with the guarantee that it is assumed to be unplayed. Unplayed records will always play better the 1st time unless. of course there was a factory flaw. A sealed record cannot be inspected for flaws in the vinyl's grooves, so it not wise to call a sealed record MINT. Sealed records have sold for more than the high end of price guides. If
you are selling sealed records, be advised that many collectors shy away from them. A sight unseen record (through mail order) is hard to sell. A sealed record is even harder to sell. If you sell a sealed record and the customer finds flaws (such as paper scuffs or defected vinyl) you won't be able to claim that the damage was caused by them, or that they swapped a good pressing with a bad pressing. If you sell sealed records, you will have problems with some people, so be alert to those claims of overgrading sealed items!

NEAR MINT COVERS: The cover should look as close to perfect with only minor signs of wear and/or age. Minor impressions to the cover (due to the outer edge of the vinyl resting inside) may be acceptable, however the artwork should be as close to perfect as can be.

(This will be explained under a different topic.
.FAQ: How to value your collection based on grade)

EX (VG++) VINYL: An excellent (or VG++) condition for vinyl will allow minor scuffs which are visible but only slightly. There may be more than a few, so be careful not to call a record that has wear to more than 15% of the surface -EX. The wear should be minimal and of course should play mint! Any scratches that can be felt with your fingernail can NOT be called scuffs. Scuffs lay on top of the grooves. If there any break in the grooves that can be felt, they ARE scratches. And most often, they will be heard when played (soft clicks or even loud pops). Once again, "No scratches can make this grade"! Only a few minor paper
scuffs and that's about it. The play should be close to perfect as well!

EX(VG++) COVER: Artwork should still be as close to perfect as can be. Some impression to the cover (minor outer ring wear) but no ink wear! Some slight creases to the corners, but not wrinkled and obtrusive to the eye. The corners can show white (where the artwork pasted slick was) meaning, slight wear. No seam splits or writing on the cover or taped repairs can make this grade. If you don't think a cover is NM than call it EX or less. There will be obvious reactions to the EX grade but if you use the EX grade and price a bit lower, your risk of overgrading will be reduced dramatically. You will also make more people happy, rather than trying to call it NM.

VG+ VINYL: Now for LP's (the big ones <G). VG+ will show wear, surface scuffs,(or spiral scuffs that came from turntable platters or jukeboxes for 45 singles)and some very light scratches. Surface scuffs are caused from blunt (not sharp)objects. Often the minor scuffs are caused from inner sleeves. The vinyl should still have a great luster, but the flaws will be noticeable to the naked eye. Sometimes holding the record up to a very bright light you will see many tiny lines across the surface. If the flaws don't cause any surface noise the vinyl can still make the VG+ grade. Most (but not all) VG+ records should still play like a NM record. Because the vinyl has more than 15% (yet less than 30%) wear to the surface it can make this grade. Remember, the record still should look as though it was handled with extreme care. Sometimes people find records that have no scuffs that are visible, yet a careless needle scratch causes a break in the grooves. Play the record. Any obtrusive clicks or pops, which cause the song to be less than enjoyable, may not even be VG+! Be cautious! Scratches are not acceptable to a serious collector in any way. If you call a record 95% NM but note the record as having 1 track with a bad scratch, many will only consider it as VG (explained next). You should seldom call a record "A Strong VG, plays mostly VG+". Remember the more conservative you are about the visual and audio part of the grade, the better chance you will not have complaints from those who buy from you. Be honest. If you were buying that record, what grade would you say it was? There are many serious collectors in this market and they won't hesitate to call your grading lousy if you put a VG+ grade on a record that plays less than great.

VG+ COVERS: Now that we defined the EX grade, a few extra flaws will make this grade. A virtually clean cover but may have small writing on it. (Magic marker in big letters will not cut it. They are an eye sore so be wary of overgrading).The artwork should look clean with slightly more aging. The back of the cover usually gives away the age of the cover. Flat white paper will be somewhat yellow yet no stains or mildew from water damage. Some minor wear to the seams or spine, but no tears or holes popping through. The corners will be slightly dog eared yet no crackly bends defacing the artwork. In essence, a VG+ cover should have no more than 3 flaws mentioned. If all apply, it is less than VG+. (see next grade below)

VERY GOOD or VG: This grade has become the much lesser demanded item. A lot of people feel that a VG record is a record that is good enough. They are not really going to look very good, but they should STILL play very good. there will almost always be some surface noise when they are played. The Dynamics should still be excellent, overpowering the surface noise. A VG record will appear to have been well played but still have some luster. The vinyl may be faded, slightly grayish, because of surface scuffs, which often happens to records that are played and left out of jackets. Still they should appear to have been handled as carefully as they could have been. Records that get continuous playing time will always start to deteriorate. Records that get less play are easily evident since they almost always look as though they
were played only a few times and then packed away for decades. More and more surface scuffs and scratches, and audible sound defects WILL be heard. They should not overpower the dynamics of the music. With VG records, the surface noise will be minor crackle or a slight hiss, but should only be heard in between tracks or in low musical passages.

IMPORTANT NOTE:
With Jazz and Classical recordings, the music can become very low to the
point where no music is even heard. If any crackle, tics, clicks or pops are heard, these records will have very little value to a serious collector! Classical and Jazz is seldom wanted if they are in less than VG+ condition. It is wise to play these records (as you should all records) when evaluating grades. Some classical records may look VG+ or even NM, however play less than perfect. Beware of overgrading these. They are difficult to grade and conservative grading is a must with them. and equally as important. Most dealers truly will not have a lot of time to play every single LP they sell. It is just impossible. However when records have questionable flaws, the record should be tested at least where the flaw occurs in the playing surface. Visually noting the flaw may not be good enough. If the record skips, you will have made a mistake and the value would thus be much less. A Classical LP in VG condition often will only be worth 10% of the NM book value. If they are even wanted at all.

GOOD or G (including the G+ and VG- grades)
A good record will look very well played, dull, grayish and possibly abused. However a Good record should still play. It will have distracting surface noise, such as crackle that is continuous or some hiss. Will also have some loss of dynamics caused from grooves being worn. It should play without any skips or any obtrusively loud pops or repeated clicks caused by deep scratches. If you can't enjoy the record, it is no longer even good. Good means that it will play with some form of decency, so one can still enjoy the music even though you can still hear noise caused from the wear. NOTE: Rock and Roll records generally play loud. G condition records for
them will be the most likely thing that will still sell well. Jazz and Classical and easy listening in G condition are almost worthless to a collector, since the musical passages often get very low and surface noise is too distracting to the listener. Also check on 45 singles for the length of time. Records that play longer than 3 minutes, may not be as dynamic and thus any wear will be heard more than the music (overpower the dynamics). Use conservative judgment when grading these types of singles.

***NOTE: Sealed records that have water damage should be opened. Otherwise you will be in trouble later on when the cardboard starts to deteriorate inside the shrink-wrap. Attempt to dry the covers using a hair dryer (be sure to remove the record first!)

G+ and VG-: This is separate from the above. Many records that appear in VG condition often play less than very good. Goldmine defines them as better than Good, but less than Very Good. The value should not increase more than the value of a Good record. Meaning they all should be priced somewhere within the same guideline (most often it is 10 to 15% for Good, and only 15% for Good Plus (G+) and Very Good Minus (VG-).
With a G+ record, it will look just as the described condition for Good,
yet may play better than it looks. Dynamics are usually good enough to overpower the surface noise. Same for VG-. However VG- and G+ are of the same value. It is more of a visually and audibly combined grade. There should be no large price increase for these records. Price them like G records and you should not have a problem.

Beware of imports from countries such as Taiwan and Korea. Although the
vinyl appears thick (almost too thick), the sound mastering and plate mastering are inferior. They sound as bad as bootlegs, since they were mass produced using less than superior technology. They also were placed in paper sleeves that looked cheesy. Some may sound better than others, but beyond that, they are not very collectable. They are more of a conversation piece rather than a valid piece of sound recording. Collectors often just pick them up for the novelty factor, not because they expect them to play good.

M+ : They are trying to say the record is better than MINT! No such animal. If you see this grade, avoid the record like the plague. Mint is the highest grade anything can ever be. And 99 out of 100 times the record won't even be mint! Man is not perfect! So how can a man-made product be better than perfect? Answer: Impossible.

NM- : Near Mint Minus. Just another way of trying to get top book value for a record that is less than NM.
If a seller uses this grade, ask what it means (thoroughly)
as opposed to the NM or M- grade. It's your dollar and
if they are selling it as less than NM yet for top dollar,
you may be out of luck trying to convince them that it
was an overgrade on their part. If a record is slightly
less than NM, then use EX or VG++.

EX+: If you read the above the same rule holds true here. No such thing as EX+. It is just another confusing grade
that does not have any defined level of agreement among
collectors. People who use this grade don't want to lose
money on their collectibles. By upping the grade, means
upping the price. Just be fair. Use conservative grades
When you grade a record, put yourself in the shoes of
the potential buyer. Would you want to get a record with
this grade and discover some overlooked flaws?
If you sell a record for big $$$ be prepared for criticism.
People will examine the record with more than just a quick
glance once they receive it. Overgrading will only make
you look bad. And too many unhappy customers means
very few repeats (or perhaps no customers in the long run).

VG+++: Come on, 2 plus marks are enough! No such animal!

G++ : Ok so I use it once in a blue moon. But at least I describe the way the record plays, to a tee!
The price does not go up. The grade is just a good
selling point. Realistically though it does not exist.
Use it seldomly, if ever