http://stereopsis.com/flux/
Not so much an in-game tip, but a way to keep your eyes from going FUBAR. From the site: f.lux fixes this: it makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day.
It's even possible that you're staying up too late because of your computer. You could use f.lux because it makes you sleep better, or you could just use it just because it makes your computer look better.
A free program that is absolutely amazing. I had problems getting used to the yellow'ish hue at first, but now I can't do without. And my eyes love me for it.