This is a great question! Picking up new skills is so important for developers because the landscape shifts so quickly. A while back, a lot of people asked me this question so I wrote an article about it: css-tricks.com/learning-to-learn
The tl;dr is:
try to identify holes in your knowledge- this can include looking through course structure online, or looking at API docs, etc
then write down and schedule all of those pieces so that you can devote some time to it, and mark things off little by little
I make sure I'm practicing the new things I'm learning- if I have to learn it for a job, great! That's baked in to the process, but if I'm just trying to level up, I might make a side project so I learn it.
Making something I enjoy really helps me learn because I'm more incentivized to do it
I also pay attention to how I'm learning, that I'm doing what works for me