I tend to write in fragments -- not in sentence fragments, but rather fragmented paragraphs. Instead of starting at the beginning with an introduction and then taking that through to the body paragraphs and a conclusion, I jump around the page, starting one paragraphs when an idea hits me and taking it as far is it goes, before jumping over to another thought. Sometimes I'll make notes for what a paragraph is going to be about, and sometimes I'll just leave a blank space to indicate that some sort of transition is needed still between one idea and another.
Oftentimes, I'll save the introduction for the very end -- I find it's easier sometimes to write an introduction to what I'm going to say after I've already said it. This happens more often when I'm not entirely sure where my writing is going to go, like when I'm writing for my blogs. In those cases, I'll often start with a topic or subject but not really be sure what I'm going to end up saying about it, so the introduction ends up writing itself once I've finished the body. When writing professionally or for school, I'm more prone to start with the introduction, which helps me focus my thoughts and gets me started.
I think that younger, novice writers tend to write fairly linearly. In general, that's how English teachers teach writing -- at least, that's how my teachers taught me when I was coming up through grade school and secondary school. I first learned the classic five-paragraph format; the introduction, three body paragraphs, and a conclusion, in that order. Instead of bouncing around a piece and following whatever stray thoughts came into my head that might be useful, I focused on a very regimented order of what to write about. I think this can cause one's writing to suffer, because we don't necessarily come up with ideas in the order we want to -- if we don't follow a thought, we may never get it back again.
Of course, this style of writing contrasts with the model presented in the article by Flowers & Hayes, which talks about a more fluid style of writing in which the processes of generating ideas, "translating" and revising all happen in waves, rather than as separate actions. Many students dislike pre-writing activities -- and while I believe that a traditional outline can help in certain situations, I understand the frustration with breaking things down in that way. A more natural way to write is what's presented by Flowers and Hayes.
