"How to write in style?" -Vonnegut

The rules by Vonnegut that will be hard for me is "Do not ramble though" and "Have the guts to cut". When I am writing papers/essays I like to write a lot of detail to express the topic, but sometimes I tend to write to much stuff that is not needed. I start to ramble on and on and start writing whatever comes to my mind about the topic. Then when I read over my paper I usually have more detail then needed but if it sounds right then I leave it and don't cut it out. I'd rather leave the extra detail in my paper and not need it then to need it and not have it.