In light of these guidelines, analyze your current typing style. Your chair may be too high. Perhaps your desk is too high for you, or you are too close to the monitor with the chair pushed in. Our body types affect the final arrangements to some degree. Once you've constructed a high-quality environment for typing, don't undermine your own efforts with bad habits.
Some typists take out their aggressions on the keyboard.
Perhaps this is safer than doing so on the commute home, but it greatly increases the risk of wrist and arm damage. Use as light a touch on the keyboard as possible. Don't type with the telephone cradled on your shoulder. Watch for hunched shoulders. And it's important to take breaks on a regular basis.