As with any good habit, it's important to reduce resistance. If you want to eat healthy, have juicy apples at hand in the fridge.

I made a conscious decision to start installing all my dependencies into a folder within my project source-code so that I can painlessly jump to the dependency's source and read it. (E.g. in the Ruby world, this means installing to "./vendor" in your project).

The effect of doing this is that it's easier for me to read the source code of a library than it is for me to leave Vim and look up the docs online. Voilà, now I'm reading more source.