Don't screw around. Carpal tunnel surgery seriously sucks. I got both of my wrists fixed a couple of days before my 21st birthday.

Things that have helped me... Make yourself aware of your posture and wrist location. Don't type with your wrist bent at funny angles. Run something like workrave or xwrits and force yourself to take breaks. Exercise. I switched from emacs to vim because I couldn't train myself to use opposite hands for the ctrl key and the letter key. Stretch. Try out different keyboards. Try out different keyboard heights.