The problem with "learn x" from a motivational standpoint is that it is extremely open-ended. Say I want to learn more JavaScript. How do I know when I've met my goal? If the goal is indefinite, how do I measure progress? This is very demotivating.

Instead, try to find something completable which requires the skill you want to get better with. Build something, even if it's mostly frivolous. You need a destination, a path from here to there, and the ability to measure progress along the path.