Personally I take a "flow approach". Sit down, and write every thought that comes to your head about the topic. Eventually you'll run out of stuff to say on the topic - tada! You have your first draft.
Next, go through and delete anything that's irrelevant, then go through and re-write any sections that don't feel right. Now you have your second draft.
Now, rewrite out the -whole- thing whilst only using the second draft as a guide, not a definitive copy. This may seem unnecessary, you'll think "but I've already changed everything I'm going to chage!", but you haven't.
When you go through this final time you'll shift words around, you'll add new sentences, you'll replace sections again - because you're thinking over it all for the third time. After this, do a quick run through for spelling/grammar errors, and bam! Final copy.
For maximum effectiveness take a break between each step so you can view it with fresh eyes each time. This way seems to work the best for me, and everyone I've tutored, because unlike brainstorming and headlining you haven't boxed yourself in from the beginning - you've just emptied every single thought out and eliminated the poorly formed or poorly written ones.
Hope that helps!