Sometimes in spite of layering, pinning and starching some quilts do not want to lie completely flat. I've come to the conclusion that it is a number of factors. Your choice of batting definitely plays a huge role. Polyester bats will not lay as flat as a 80/20 or W&N. High humidity also affects the fabric and some cottons just like to wrinkle and stretch more than others. If you haven't pressed well or try to hurry with your pinning, it may also affect the outcome. Some of my quilts are definitely flatter and smoother than others but I've never had a new quilt owner yet complain that their new quilt is not as flat and wrinkle free as the ones in the juried show. Do your best to control the variables and quilt on!