When people ask me what they should learn to get better at something–playing piano, programming, doing math–they want me to tell them a particular skill which they should focus on.
My response is usually that they should just do whatever they enjoy the most. If you’re trying to learn piano and you’ve been really enjoying playing pop songs recently, then just learn more pop songs, and learn to play them in more keys. If you enjoy making dumb Javascript games, try to make a more elaborate one.
The most common way that people fail to learn a new skill is by not practicing it enough. So if you want to learn something, your number one priority should be to make sure that you’re going to enjoy whatever you’re going to do to learn it.
How do you find the fun ways of learning a skill? I don’t know in general.
For the specific case of learning to play music: It’s pretty easy to learn enough guitar or ukulele that you can play songs on them; that’s my recommended approach. Jeff Kaufman echoes many of the thoughts I’ve expressed in this article in this article of his about learning music .