I've entered two contests. The first was a juried show and I was dumbfounded that two of my quilts were accepted. I didn't win anything, but the feedback from the judges was great. I had no idea what all they looked at. It was truly a learning experience.
Last year, I entered a show and won "Best Wall Hanging" and "Best Machine Quilted," one of the proudest days of my life. I admit I was, and still am, very proud. It's one thing for people I know to compliment my work, they love me!
It's a different feeling all together when a total stranger validates your work.
Enter everything you can. It's a blast and I guarantee you'll learn from the experience.