Strategies for invention

When I write i ten to think aboutit alot before i write so i know what i am going to write down. It seems like once I start it either is just a bunch of random ideas or i leave out information that i wanted to get in because i over analyze it. When I do write it is usually Brainstorming or free writing i dont ever really loop it gets me all confused and jumbles up in my thoughts cause i would tend to get unorganized. I think it would help me to do alittle less braing storming and just try and get all of my thoughts out so i dont erase something because it is worded wrong.