On serendipity Robert Greene describes the process of mastery as heavily dependent on serendipity. In order to reach an intuitive level of mastery, you have to expose yourself to enough facets and dimensions of the thing you want to learn (directly and indirectly) to develop the intuition. It is through many layers of understanding that they will all begin to blend together. That's really awesome to hear when in the context of masters that are already experiencing it daily, but it is not so for yourself. The way to get there is simple—make it your goal. If you are deliberate in never spending a moment of your life "dead," then your time will be better spent. There is a lesson in every moment. You can always be taking advantage of your time and it can always help you on the path towards mastery.
On big problems I would also recommend that you find a single big problem that is extraordinarily difficult to solve and make it a constant subject of your thoughts. Just like Einstein was able to rack his brain over his thought experiments, you should have large enough questions that you can think about them at every hour of the day and still not solve them. This may even become frustrating when you're completely failing to figure out a solution—good. You'll have to keep challenging yourself to learn more in order to develop a more intuitive sense of the problem and find a solution towards it. Use this as your approach to your learning and your innovation.
On sleep Your entire condition deteriorates quickly when you are tired. You become irritable, frustrated, and even sad. You are not like this in the morning when you wake up early, because (after a couple minutes of waking up) you are refreshed. You need to sleep effectively. This either means you start going to bed earlier to wake up at your standard time, or sleeping less and napping some time during the day. If you can't nap during the day, then you have to go to sleep earlier. I've seen you go too many days without a nap during the day and you're left exhausted by the end of it. Then, you sleep in on a weekend and abandon your industriousness because you failed to plan out how you would work and maintain your condition at the same time. Sleep, and don't hesitate to. You know when you need sleep. Listen to that.