Constructive Criticism
Take a look through the artist’s eyes.
Try and see what the artist is intending on doing, and try to view the piece from there standpoint.
Don’t nit-pick the little stuff.
Don't harp on the little stuff, try and mention improvements but don't center your whole constructive criticism on that one flaw.
Of course, if the artist asks for a nit-picky critique (and some will) then go ahead. It might not be the best way to help, but at least you know they won’t mind.
Start positive and end positive.
Always try to make sure to start off by saying something nice. Even if it’s difficult, find something to say.
After that, be as honest as possible—without being heartless—and then close with another encouraging, positive statement or a positive suggestion.
Artists can occasionally be sensitive about their art (a little known fact) so it just makes sense to cushion the blows a little bit.
Never be vague.
There’s nothing worse than a vague critique. They usually sound a little bit like this:
“ Not bad, Better then I can do :P .”
The truth is, if you don’t have anything to say about the piece it’s probably better to not post as it will most likely be deleted.