Pills. Failing that, everything everyone else has said... if you find yourself procrastinating too much, get medicated.

On top of that, routine, regiment and willpower.

I started learning Russian recently, trying for the second time. This time around, I found that the small positive reward gamification elements of Dualingo to be a great help (Streaks and daily bonus BS currency).

I've also found myself using Trello to list out things I need or want to do to stop from overwhelming myself. If I have a new task or thing I need to do whilst I'm already getting something else done, I note it down and then forget about it until it's time to find something new to get done.

If all else fails, then look at yourself. Take a long, hard look at yourself in the mirror. I became good at this through necessity, after illness and injury I realised that there's no time for chronic procrastination. If your life expectancy halved what would you change and how quickly?

If you still can't fix it, I'm guessing it's not as big a problem as you think it is... enjoy yourself!