Try a new library, or language, or feature of a language as often as possible. Experts become experts by mastering a ton of tiny things.
Personally, I'd rather go deeper in what I'm learning on at the moment and finish something substantial before diving into some other topic. It probably depends on how much of a multi-tasker the person is, but I find it difficult not to concentrate on one topic at a time.
I do understand what you're trying to say, though.