Decide what to work on. It has to be something you have a natural aptitude for, that you have deep interest in, and that offers scope to do great work. The way to figure out what to work on is by working. If you're not sure what to work on, guess. But pick something and get going. You'll probably guess wrong some of the time, but that's fine. It's good to know about multiple things; some of the biggest discoveries come from noticing connections between different fields. Develop a habit of working on your own projects. Don't let "work" mean something other people tell you to do. But always preserve excitedness. When in doubt, optimize for interestingness. A field should become increasingly interesting as you learn more about it. If it doesn't, it's probably not for you. One sign that you're suited for some kind of work is when you like even the parts that other people find tedious or frightening. Learn enough about it to get you into one of th...