Preface: I am not a doctor, nor am I professional ergonomist. Please talk to a professional if you think you need help.
For most of the people reading this, you spend at least eight or more hours sitting at a computer. Doing this while not taking care to have good posture can lead to some serious negative effects.
Sit or stand up straight, with your upper arms either parallel to your torso, or at max 30° in front, facing the screen head on.
Take a short one minute break every 30 to 60 minutes. If you’re standing, sit. If you’re sitting, stand.
Find the time and research things that will improve your setup, and know that no two people are the same.
Speak to a professional about options. Some HR departments have specialists on staff.
Keep a nice ambient light while using the computer.
Slouch or lean back in the chair while typing, it’s so easy to do, and is a huge pain to break the habit of.
Sit with your wrist hanging off the edge of the desk.
Sit twisted, with your body in torsion to look at the screen.
Ignore itching, burning, or tingling sensations in your hands. Nerve damage is cumulative.
Sit in a dark room staring at a bright screen, or sit in a bright room staring at a dim screen.
Remember to take care of yourself, there’s only one of you.