DOUJINSHI (FAN ART)

What to keep in mind when commenting: doujinshi is NOT professional art! It isn’t perfect all the time! Don’t go bashing/flaming/cursing an artist just because their drawing of Sasuke isn’t like the mangaka’s or because they imagine other situations for existing characters (for example, yaoi/yuri pairings). That is the first thing you have to keep in mind all the time.
Also, doujinshi does not refer only to anime/manga-styled drawings; it can also depict a film/game/whatever character or situation. Basically, doujinshi is artwork drawn by an artist of anything he/she wants.

How to judge doujinshi: first, let’s take the character. Is it well-positioned? The fact that it’s not a professional drawing still stands, but not to the point where you flame the artist for not drawing the character in any position drawn before by the original creator of the anime/manga/whatever. By well-positioned I mean in a natural pose, be it a fight pose or a stroll pose. If the character’s legs/arms are twisted in an unusual position (and the artist doesn’t explain WHY it is like that), you can consider this a goner.

Second, the coloring. Does it look out of place? Does it fit the character? You shouldn’t even be able to tell the colors apart; the doujinshi should appear like a perfectly colored piece that you couldn’t imagine otherwise - in one word, “perfect”. What am I saying here? If the colors match the character and drawing style and look natural, we’ve got a winner!

Third, the background. This is optional. Some artists (like me) prefer to leave a blank background because they don’t feel like working on the piece anymore. Fair enough, sometimes it’s better to leave the background out if the other elements have a lot of details. Remember this when commenting and don’t just say “this needs a background” when it’s obvious a background would mess up the whole thing.