A comfortable an ergonomic computer work is very important to protecting your health. I trie to put some advices:
1.-Use a good chair with a dynamic chair back that is angled slightly to the rear.
2.-Top of monitor screen should be 2-3" above eye level
3.-No glare on screen; use an optical glass anti-glare filter where needed
4.-Sit at arms length from monitor; further if distance is comfortable and screen's readable.
5.-Rest feet on floor or on a stable foot rest (move feet frequently for circulation)
6.-Use a document holder, preferably in-line with the computer screen
7.-Wrists flat and straight in relation to forearms to use keyboard/mouse/input device
8.-Keeps arms and elbows relaxed close to body
9.-Center monitor and keyboard in front of you
10.-Use a negative tilt keyboard tray with an upper mouse platform or downward tilt-able platform adjacent to keyboard
11.-Use a stable work surface and stable (no bounce) keyboard tray
12.-Take frequent short breaks (micro breaks) and stretch.