My best guess would be that you are not starching stiff enough. I have very little raveling when I piece my tops. And when I press the seams they are really flat. I use Sta-Flo starch mixed half with water. I buy it at Walmart and I should own stock in the company. I dampen all my fabric (if there is yardage I put it in on a rinse cycle in the washing machine). Before it has time to dry I spray it with the Sta-Flo and allow it to dry. Then I press it. Believe it or not I have very little reveling. Then cut out your pieces, I think you will be amazed with you end results.