Three things make long study days possible for me.
Enjoy
Trying to approach a topic one is indifferent to can be a little difficult. I try to make sure I enjoy the topic—how and where it is used, how it may be useful to me, why I should care to explore the topic, and so on.
Personal Catalysts
An emotional/personal catalyst is a great source of fuel for studying when one doesn’t feel like doing so: some people feel that they are robbing themselves of their future (or working toward achieving their future), some experience strong emotions in the process, some study for their (future) kids and family, and so forth. However, the underlying principle is the same: a catalyst.
Environment
Studying in an encouraging environment with like-minded people who are more experienced definitely helps. Even if not possible in real life, the Internet exists!
“Tell me who your friends are, and I’ll tell you who you are.”
If you’re in a room with 5 gentlemen doing 100 pushups every day, in the end, you shall start doing them too.
- Nihad Badalov