If you're anything like me, or anything like 90% of humanity, you can't rely on motivation to progress in life (whatever your idea of progression is). None of the platitudes or self-help-shaped advice you read here or on Reddit will help you with that. You can't trick yourself.

What works for me is, as much as I don't like the word, discipline. I take an hour every week to review my routine and plans, when I'm inspired and motivated. The rest of the time, when I'm not motivated, I spend executing what I wrote down. In the beginning you will feel miserable, angry, and sad. But after a couple weeks you get used to being your own boss. No matter what you feel (unless you're physically ill), just do what's written down and defer the decision making process (is this what I should be doing) to that planning hour.