keep your screen dark

I usually set brightness and contrast on my LCD monitors to a minimum. It seems the text is harder to see this way, but the fact is weaker backlight can save your eyes a whole lot of strain. Still, when direct sunlight gets through my window the displays become almost unreadable. So yesterday I tried setting my laptop and my big display to a medium level of brightness. It took me a whole day to realize why my eyes were so sore (I thought I just had too little sleep). Turns out the backlight really is the killer.

My e-book reader doesn't have any backlight and you can read it 24 hours straight without getting your eyes tired.

Another thing to remember is that usually white text on dark background is easier for your eyes to read. It's a pity that way too many web sites are so overdesigned that you can't override their color scheme without losing a significant chunk of usability.