The trial and error rule applies to me. I do what works for me. Since there are no hard fast rules of how to get the end result, I just plow through the process. Keep working it until I find something I'm happy with. I have settled into my own "rules" I pre-wash. I starch. I have a stash because when I'm in a fabric store I cannot ignore all the pretty fabric that calls my name. I also never usually have exactly what I need, so I buy more. For me, less is more. If I muddle the water too much, I get confused or frustrated, so I go back to my basics.