I read books on programming. The thing I most like about programming books is that they allow you to learn about topics that you would have never have thought to explore. When people look things up online, they tend to search very specific things, most times actual code. The internet is an incredible source for developers, don't get me wrong. But books allow you to learn about programming in a conceptual way which in turn will make learning new languages easier and allow your understanding of the languages you already know to be deeper.