Spend the minimum work necessary to excelI don't quite agree. Students are too concerned with getting good grades.
Good point -- what I meant by "excel" was mastering the actual subject matter. You're going to need to master a large number of subjects, some of which you're not particularly interested in. Focus all your school work on mastering those subjects -- especially the ones that aren't easy for you.
Then, for the things you really like, go off the reservation and do your own thing, but under your own auspices. For example: Even though you may love game AI, don't try to cram an advanced Starcraft play bot into your comp sci curriculum. Instead, do the simplest possible project that will show you have mastery within the Comp Sci curriculum, and then separately work on the Starcraft play bot outside of school. And I repeat: Do the simplest possible project that will show that you have mastery. This will let you take the interesting work in any direction YOU want to go, without worrying about it hitting a particular curriculum requirement, or particular schedule.
Same thing for robots: Don't try to cram your favorite robot project into whatever class it might fit. Instead, pick a simple project that will demonstrate mastery within the class, and work on your robot in your own free time. (This is assuming that you are able to achieve mastery within the class -- if you don't, then you shouldn't be spending too much time on your own projects at all :-)
Being very clear about what is school work, and what is your own work, will make it much easier to spend your time wisely.