1) Good, regular sleep. ADHD symptoms are way more controllable when I'm well rested.
2) Stimulants: caffeine and Vyvanse. I also had a prescription for Adderall, but it has some nasty side effects for me so I rarely take it.
3) Accept that it's hard to focus on stuff that doesn't interest me, and plan accordingly. (Including career choices.)
4) Work in person, rather than remotely. I'm too tempted to screw around when I'm not around coworkers.