Starch will help! I starch my fabric before I cut it, and it really helps keep both cutting and sewing straighter and crisper.
I also found that using leaders/enders stops me from pulling, and keeps the machine from eating the first edge of the seam. <leader - a wee bit of scrap fabric you stitch across and then abut the patches you're sewing - a 'starter' chain; ender - I use the same scrap to finish the chains. Bonnie Hunter has tons of patterns to create quilts out of scrap leaders/enders, but when I don't have scraps organized, I just reuse the same scrap over and over.>