It would be really handy if there was an XP tracker in the level bar. It would just be text telling you how much XP you've earned, and how much you still have left or have to earn in total. This way it would be easy to see how much XP grading/making one homework gives you, and using that, it'd be easy to set grading goals.
I think something like this might be best:
Customer support service by UserEcho