I sometimes find that just summarizing a video or audio lecture every few minutes helps -- and active watching/listening. It's easy to fall into the trap of tracking details and missing the point, much like reading all the words on a page but failing to take away the main idea.
You might also like something like www.videonot.es -- though I suppose "your mileage may vary".
I have tried a lot of things -- setting alarms, putting up notes for myself, setting reminders on my calendar, etc. The three things I have found that really work for me are (1) having a jam-packed schedule so that if something is a priority I have to do it at such-and-such a time; (2) just forcing myself to repeat a schedule every day (but re-lapsing is so easy); (3) Having just one must-do habit each day: completing a checklist at the end of the day of what I did and didn't do -- basically, forcing myself to recognize that I didn't do certain things to gently guilt myself into doing better tomorrow.
A bonus (4) would be deciding a couple hours ahead of time that I have to do something: at 3pm, for instance, telling myself "you have to study for at least 30 minutes at 7pm".