My first draft is always very similar to the finished product. I basically just write things how I intend for them to be in the end, then read through it a few times. Sometimes in reading through I'll just tweak a few sentence structures or wordings, sometimes I'll add whole sections or paragraphs.

I'm sure this wouldn't work very well at all if I was writing a novel or something, but with what I do write it works just fine - generally the stuff I write doesn't even have chapters, and it tends to vary from things with less than 1,000 words to things with 16,000 (plus prequels and sequels).