I'm not quite sure what you are after here. If it's about how to motivate other people to learn, those are teaching skills, and I am pretty lacking in that regard.

In terms of self-motivation, I think it is important to take stock once in a while of how far you've come. For example, say you're learning a musical instrument. It's so easy to get frustrated. You can't figure out how to play that new song or master a technique. And then you see some other guy playing the same instrument in a different band and they're killing it.

What I find helps in that situation is to think back to where you were a year ago. You're doing stuff you couldn't before and it shows. Give yourself some credit for putting in the work and getting results. Pat yourself on the back and be proud for once.