I steam and starch my fabric before cutting quilt pieces. I figure any distortion will happen before cutting so I won't have to worry about it later. After sewing the pieces I use a dry iron and a Tailor's Press to flatten the seams. The wooden press takes all the heat away from the fabric in seconds. Moving fabric before it cools is a no no for small pieces.

I'm with BellaBoo. I also use steam and when needed, a tailor's clapper.