Have you tried going through the pictures you love and writing down what you like about them? This may give you a clue as to what you need to do to yours. For instance, I really like a narrow (1/2") border around the center blocks of a quilt. I like black or a high contrast color for this border. It may be that you are drawn to particular color combinations, or maybe you have been piecing and you really admire applique.
If it is your workmanship, the the solution is simple...practice, practice, practice.
I would like to seem some samples of your quilts also. Maybe you are being too hard on yourself.