My problem with sleep in general is that I need about 8 hours to function and to get the most out of exercise and studies, but I have a much easier time getting up if I'm sleeping only 6 hours or even less. Haven't found a solution to that.

But if I allow myself to get up after 6 hours of sleep a combination of having drank too much before going to bed and not closing the blinds works best. I know that sleeping in perfect darkness is supposed to be a good thing. But getting up in the darkness doesn't work so well for me. The need to pee is a strong motivator as well.