0) Introduction
What others find near mint, others find played. Most flawed condition grading is done by sellers who want to make quick cash and most correct grading is done by experienced sellers. Very logical and you should keep this in your mind. It's very wise to always ask for a picture of the card you want to trade since it's very easy nowadays due to all the smartphones out there.

The condition grades given in this thread are gathered from official sites who are experts on grading cards. The idea of this thread is to diminish subjectivity when grading a card.

A card has two sides: remember to evaluate a card using the worse side!

1) Condition Grades
MAIN GRADES
MINT (M)
No printing imperfections or damage visible with the naked eye. Very minor printing imperfections or damage upon close inspection. Clean gloss with one or two scratches.

NEAR MINT (NM)
Noticeable, but minor, imperfections or wear on the card. Solid gloss with very minor scratches.

EXCELLENT (EXC)
Noticeable imperfections or moderate wear on the card. Some gloss lost with minor scratches. No creases nor tears.

PLAYED (PLD)
Heavy imperfections or heavy wear on the card. Almost no gloss. Minor scuffing, very minor creases or extremely minor tear.

DAMAGED (DMG)
Destructive imperfections or wear on the card. No gloss. Heavy scuffing, severe tear or heavy creases.

SIDE GRADES
GEM MINT (GEM)
Perfect card. No imperfections or damage visible with the naked eye and upon close inspection.

MINT / NEAR MINT (M/NM)
This is the most used grading class of side grades. No printing imperfections or damage visible with the naked eye, but slight printing imperfections or damage upon close inspection. Solid gloss with very minor scratches.

NEAR MINT / EXCELLENT (NM/EXC)
Noticeable, but minor, imperfections or wear on the card. Mostly solid gloss with minor scratches.

EXCELLENT / PLAYED (EXC/PLD)
Noticeable imperfections or moderate wear on the card. Heavy gloss lost with very minor scuffing, and an extremely subtle creases or tears.

PLAYED / DAMAGED (PLD/DMG)
Severe imperfections or wear on the card. No gloss. Noticeable scuffing or tear.

2) More on Card Grading
Blackborder - Card Conditions
Star City Games - Card Conditions
TCGplayer - MtG Card Conditions
MagicCardMarket EU - Card condition
Card Kingdom - Grading

3) Additional Thoughts

I will complement this thread later based on the multiple sources I already have found. Nevertheless, I have been using these condition grades for quite a while and they have worked like a dream.

If you have questions, you can either ask here or send me a message.

Regards,
ELTP

I have a question, since the grading is mostly based on the card condition, with points taken off for creases and scratches. How would you rate cards which have a bend in them, which has developed naturally due to humidity and time. Since I have some old DM promotion cards I found which I wish to sell.