How to get things done before deadline approaches?

Hey All
When my teachers assign work or tell us about tests, they tell us quite a while before. The thing is, I can never start working properly until the night before its due, and its getting to be a problem.

Its not like i don’t try, but when i open up a book or a doc file, say a week before a deadline, I just cant concentrate, and whatever mediocre work i get done just doesn’t cut it in terms of what the teachers expect.

The nights before, however, i am at my best, i can concentrate fully, and it’s like they’re the only times my brain functions properly. I’ve had this quirk my entire life, but it’s only a real problem now that I am a senior and the work is sufficiently harder.

How can i convince myself to work every night like its the night before the deadline?