If you are like me you're 6 foot 2 and your name is Kevin. Also you spend most of your day staring at a monitor of some type. I have some advice, I don't know how well they will work for you, and I don't know if there is anything to back up my reasoning behind these actions, but they seem to work for me.
1. If you can afford it get some kind of non-CRT monitor, like the ones on laptops or those nice LCD (or whatever technology it is) displays. They are more crisp. My work provides one for me. 2. Turn down the brightness. Turn it down all the way until it reaches a point just below where it is comfortable, then turn it back up 1 or 2 clicks. You still want it to be comfortable, but why stare into a 1000 watt light bulb if you can stare into a 30 watt bulb instead. 3. Turn down the contrast too. This one I remember hearing that it is easier on the eyes if the contrast is not very high. 4. Go outside a few times a day and look at stuff far away, and under natural light. Especially if you are locked in a room with fluorescent bulbs. 5. Blink. If you notice that when you are staring at a screen you don't blink, you probably should figure out a way to make yourself do that.
I have found that my eyes are less strained feeling the more I pay attention to this kind of stuff. Maybe you will too.