Ergonomics

Desk Dimensions: Have a large desk space so the computer does not take up all desk space as to allow for things like wrist rests.
Posture in Chair & Seating Hight: Firstly, one option is buying an ergonomic chair, sitting up straight and seating high should place your wrists at 90°.
Feet Placement: Should be flat and 90° with your legs.
Position of Monitor: Should be at perfect head hight so user is not looking down but straight ahead. Monitor should also be at least 20 inches away from users face.
Keyboard & Mouse Relative to User:  Ergonomic Keyboard advised, with enough space to accompany a wrist rest wrist rest. should be square 90° with the users elbow.
Rest Period & Exercises: for every two hours you should get at least 30 minutes rest and within that 15 minutes should be exercise.