> 3 . If your keyboard is lower than the desk surface, tilt the back edge of the keyboard slightly down (known as "negative keyboard tilt").
Using a slightly negative keyboard tilt will help you keep your wrists in the proper (neutral) position. Try to avoid positive keyboard tilt (i.e., where the top row of keys is noticeably higher than the bottom row of keys). Also, make sure that if there are "legs" attached to the bottom front of your keyboard, they are left un-extended.