The two questions I get most frequently when asked to comment on someone's work are:
Is it finished?
Is it too busy?
The answers are NO and YES, respectively. If you have to ask, then it is not finished. Only you can say when your piece is finished. It has to speak to you,
the artist, to qualify as a genuine expression of you. What counts as finished for me may not be finished for you, and vice versa. Is it too busy? Again, if you have to ask, then it is.
Which is not to say that you don't need occasional feedback or direction from either a teacher or another artist. It is very useful and eye-opening to get someone else's take on your work. Here are a couple of ways you might re-frame the questions in a way that may elicit more useful answers:
What do you see?
Can you suggest a couple of ways I might move forward on this piece?
What stands out to you the most?
If the person says "Don't touch it; it's finished", then put it aside (out of your visual field) and look at it the next day with (your own) fresh eyes.
But don't ask the questions until you have worked on the piece over some time, come back to it with fresh eyes, and done your own looking, seeing, making decisions. It is YOUR art, and you are the only one who can really discover what that is. The discovering is an ongoing process.
For more on seeing, observing, your own work, see my book,