I don't prewash. Lots of people do. I don't use a steam iron. I have a dry iron and if I need a little steam I use a spray bottle. I use Best Press before I cut.
Do what works for you and don't worry about what somebody else does. There truly is no one way to make a quilt. I have seen the same block done several different ways. None of them are the one "right" way to make the block, they're just different ways.