One of the things I've never (!) tried before is pressing the seams open. When I started out we were told that in quilting you were to press both seams in one direction so that the batting wouldn't migrate between your stitches and show up on top of the quilt. Batting qualities are much better now, though, and this shouldn't be an issue. I can see already that my four-patches are nice and flat, but I have to take more care with matching my seams when I cant butt the bulk of those folded seam allowances into each other. I suppose that's all going to improve with practise and pinning, though!