The placement of the monitor should be in relationship to the other components of your workstation (desk, chair, keyboard, and mouse). Position the monitor in front of you and at least 20 inches away. The the top line of the monitor screen should be at or below eye level. Consider using a flat panel arm system to adjust the monitor to your required height and distance.
Place the keyboard directly in front of you. Position the keyboard so that your elbows are close to your body and your shoulders are in a relaxed position. Ensure that your wrists are straight and in-line with your forearms. Keyboard arm and tray combinations are available in many configurations and sizes to assure proper positioning. You may also consider other accessories (palm rests, etc.) to increase comfort and mobility.
Be sure to have your mouse close to the keyboard. Not doing so may expose your body to awkward postures and lead to discomfort. Select a particular position for the mouse so that you can maintain a straight and neutral wrist posture. If your workspace does not have adequate space for proper mouse placement, consider using a keyboard tray with an extended surface for your mouse.