I have some rather strong tendencies towards adult ADHD (Attention Deficit/Hyperactivity Disorder). Completely undiagnosed, of course. Kids are frequently checked if they have trouble in school, but I never did. I think some of my success in school, and the fact that I've actually written a whole 80k word novel is due to coping techniques. I live my life by little rules that I set for myself, that help me get things done.
If you're curious about the characteristics, check out this questionaire. It pretty much sums me up. Sitting still? Am I supposed to sit still? Ahem. My attention wandered for a moment...
I think the most important rule for me is to not fight my natural tendency to let my mind wander. I am miserable and unproductive if I am forced to work one solitary task, uninterrupted, from beginning to end, if it takes longer than about 10 minutes. I do best with 2 or 3 (or more!) things going on, so when my mind decides to wander, that it has a legitimate place to wander. Right now, I'm installing software at work while I blog. I won't be any more productive staring at the install screen, really. And I certainly won't be happier.
For writing, here are a few tips (and a lot of permission slips) for anyone else who deals with these tendencies:
1) If you're afraid to start a novel at the beginning, don't. Start wherever you like. You can go back and add a beginning later. Really.
2) If, like me, you can't sit down and think through all the twists and turns of your plot before you start writing, then don't. There's a word for us among writers: we're pantsers. There's no shame in being a pantser! Write where the novel takes you--unless you're using a chisel and a block of stone, you can always edit later!
3) If you have a hard time finding the motivation to do your final cleanup, a series of edits, or whatnot, then don't. Today. Write yourself a to-do list and stick it in the same folder as your manuscript. Then, when you're either motivated, bored, or have a pressing deadline (a contest or submission request), you will have your list of tasks all ready. I always work better under a deadline anyway!
4) If you have trouble sticking to the writing when you're at the computer, then schedule yourself some downtime. Turn off your wireless internet, or unplug the network cable for, say, 45 minutes of writing. Then allow yourself 15 minutes to surf or post to your blog. Schedule your work time first, but with breaks frequent enough to keep your mind fresh and unfettered. Or, if it's really bad, take your laptop somewhere with no internet access--you will have nothing better to do than write! Just don't do that so often that you resent your writing time, because resentment is a creativity killer.
5) I find comfort in routine and repetitive physical activities. Doing the dishes. Driving in the car. Folding laundry. Exercising on an elliptical machine. It frees my mind up, and helps me untangle all of the thought thread running through my brain. I find that some of my best "writing" is done during these types of activities, which makes the words pour out of my fingertips when I'm at the keyboard. Again, I know that the sedentary activity of typing is not where I do my best thinking, so I try to optimize the keyboard vs thought stages. Getting enough exercise helps control the fidgeting too!
Sometimes I am a complete flake about a task, and sometimes it all-out consumes me and I resent every little interruption. Learn to work with both tendencies in ways that are 1) productive and 2) not damaging to your social interactions :) In everything you do, it is important to be true to yourself, and not try to force yourself to be something you're not. That doesn't mean to let your bad habits run rampant, just don't let anyone tell you that there is only "correct" way to write or think.
Ok, break time's over. Get back to your writing!