Computer posture is important. You will probably spend many hours sitting at your PC and how you do this will have implications on your health as well as your productivity.

DO
Check the position of your screen.
Have your chair at the right height so your eyes are level with your screen and your knees are slightly lower than your hip joints.
Let your wrists rest on the desk.
Let your feet sit flat on the floor and not tucked under your chair.
Keep your shoulders and back relaxed.
Take regular breaks away from your PC.

DON’T
Try to sit up straight.
Fix your eyes on the screen.
Lift your shoulders when typing or clicking the mouse.
Collapse your neck as you read the screen.
Use your PC in low light conditions.
 

Additional Tips
When sitting on the seat pan, your lower back and bottom should be firmly at the back of the seat. When correctly adjusted there should be a gap of approximately 2 – 3 inches between the back of your legs and the front edge of the chair.
The lower part of your back should be well supported and in contact with the chair back.
Your telephone should be positioned within reach of your non-dominant hand. This allows your dominant hand to perform activities while holding the phone in your non-dominant hand.