There is one tip that I think is worth mentioning:
I take a saucer and cut around it with my rotary cutter on the corners. It is much easier to crochet the curve than trying to crochet the square corners.
I only use one layer of flannel. I jus saw some of my blankets than have been in constant use for almost two years, and they still look really good.
I do use the Skip Stitch on fleece, but on flannel, I just poke my crochet hook through the flannel as I go.