I make lists. Lists (and a planner I mostly ignore) keep my on track. The "Get(ting) Things Done" method is, in some ways, making lists. Maybe that could help?

That, and pacing myself during mentally intensive tasks. I do 25 on, 10 off (more than pomodoro, because my brain). This works really well for me. You may have to adjust the variables to make it work well for you.