They look for overall pleasing appearance. Accurate piecing, even sashing and borders, binding even and full of batting to the edge, corners tacked down front and back and adequate quilting evenly spaced over the surface of the quilt. These are some of the items on the "judges form". After these are considered they decide how they rate compared to other quilts in the same category and start eliminating based on criteria and some personal likes and dislikes. I have helped scribe for judges in 6-7 quilt shows and theses are my observations.