I'm mostly just avisual.
I did spend several years in high school working on traditional art skills because I thought it would be neat to be a 3D animator.
I eventually concluded that while I was making progress, I clearly didn't have the natural abilities some of my friends did, and that it would be a constant struggle to have a career in the field.
Obviously, I now understand better why my friends had better natural skills than I did.
I used to use mindmapping software extensively to process and think through ideas and their connections (Tinderbox, specifically: http://www.eastgate.com/Tinderbox/).
I now suspect that my other friends weren't as excited by it because they could do a lot of that stuff mentally.
These days I mostly figure things out by writing plain text in Markdown files. My inner world is pretty much just words, and that's how I output things now.