Travel a lot, which breaks the day into (useful) chunks and gets physical motion in; do work as a "secondary" thing between the bouts of travel, so you don't feel guilty for not doing it (it's travel!) but an amazing amount gets done (there are an awful lot of little breaks in there).
Teach -- the regularity of a classroom and the requirement for immersive engagement motivates you.
When you study, try to have it be 1:1 as possible, and ride off the momentum from meeting your teacher as soon as you get it, for as long as it exists.
If you can't get 1:1, your memory is likely to wander during instruction you don't need to intelligently respond to. Prepare for this. Get things transcribed in realtime. Your memory will wander, but you can zip back and scroll up every once in a while -- you can bring yourself back. If you can't get realtime transcripts, use supplementary materials (textbooks on the same subject, etc) to give you the thing you can get information from when you "come back."
Set reminders for your future-self to give you motivation-kicks down the road. Automatically scheduled emails help, especially if other people (who need to be involved) are copied on them.
Catalyze groups. They're usually full of folks who can sustain things when you're spotty, and they see you as an energy-injector coming at just the right time. You do well when you're responding to the work of others coming in at real-time.
Work while eating. Read while eating. Reading keeps your mind on one topic's track; it keeps you from being distracted to other tasks while eating or whatever else you're doing.
Script out repetitive tasks and set aside time to do them. Expense reports on Fridays just marching through a detailed list of instructions. Reward yourself afterwards.