So, I'm writing this as I sit in front of my screen because as an author/ghostwriter sometimes the "ideas" and "outlines" never come when you need it and while that's
just one of the drawbacks, I feel like if I would have made writing a habit or a constant I would be having less of these "struggles".
We all know the saying "Practice makes Perfect" well that too can apply to writing. No you aren't supposed to slave over a computer until your eyes bleed or fingers fall off (Good Heavens don't do that!) but getting into the habit of things might just help (like not biting your nails, yes, you might still do it but if you practice not to put your fingers in your mouth - maybe remembering how much dirt and germs you touch every single day might gross you out - you soon become in the habit of not biting your nails.
So the same logic applies for writing - You might be able to plan/outline a little easier or get into the habit of every day or every other day (or wen you have a chance) to write 50 to 100 words. Remember doing Crossroad puzzles? Or Word games? Doing those every so often, trains your brain, and keeps your mind active.
However you do it, even if its only for a few minutes, that's enough to train your brain to learn the habit because in the long run it could help you.