you don't have to start in the center. I have made quilts using double knit as my top and a sheet as the back. I pin out a random layout of larger shapes and zig zag around them. Then do several mid size shapes in the open areas. repeat with smaller shapes till you fill the top. If you want to do it all in cottons. Baste out your larger shapes, then fold under edges of pieces on the top. you can even top stitch to make it quicker.