Actually if you don't have a specific project or problem you are working on, lurking on this forum and helping others is a fantastic way to learn yourself. You don't actually have to answer the posts, but you can work on finding solutions.
In the beginning, maybe you won't know any given solution off the top of your head, but you can still try to figure it out. You will also be able to follow and see how other people approach the issue, and ask questions.
Sometimes I treat it like a game, where each person's question is like an individual puzzle problem. I find it refreshing to work on isolated mechanics that can be completed/solved rather than my own big projects which can drag on every once in a while. Or when I'm in between my own works and don't have anything better to do