Ask HN: How do you focus?

I am diagnosed ADHD, and even my Ritalian isn't working like it used too. I flail around, and can lose myself in topics that interest me.

But, for getting actual work done, I can't. For example I quit my job to focus back on my degree. It's a bit of a personal goal to have one, although with my skill set/background, it has never been a issue getting sufficient employment.

I've tried structuring techniques, calendars, planning out my days and such. No avail.

The best thing so far is having an alarm on my phone, and snoozing it every 10 mins. When it goes off, it breaks my focus and lets me evaluate am I working on something that I should be, or am I slacking. It's effective, but, a crutch.

Nootropics seem interesting, but, being a nomad in SEA, I am worried.

How did you overcome your lack of focus?