[titanix2]

Depends on the domain. For languages, having learnt or being learning a few (including Japanese & Chinese) my approach is to first learn about the phonology. Then basic vocabulary and grammar, searching words I don’t know in the street (not everything) and having input from authentic material. I prefer learning from books using multiple one at the same time and cherry picking on what pick my interest. Having a few friends in the target language is a huge help to understand some concept or learn about cultural point. Also Wikipedia.

For other things, reading accessible research papers, reference books and searching for unknown concepts when I encounter them, sometimes ask people about a thing or two.