Your desk should be large enough to accommodate the monitor at a comfortable distance - at least 60 cm from your eyes, ideally at arm's length. Position the top of the screen at eye level or slightly below so your neck doesn't have to work throughout the session. Place the desk so that the light source is behind you, to avoid reflections on the screen.
If your desk has a keyboard tray, use it - a keyboard positioned below the desk surface is ergonomically ideal for your wrists. The standard desk height (74-76 cm) suits most people, but if you're taller or shorter, an adjustable-height desk is worth considering.
Invest in a good chair with adjustable height, armrests, and a reclinable back. The backrest should support your lower back, and the armrests should let your forearms rest horizontally - without raising your shoulders. A proper sitting position significantly reduces fatigue during long typing sessions.
Place the keyboard directly in front of you, in line with the monitor - don't push it to the side or set it at an angle. Keep the mouse as close to the keyboard as possible, at the same height - reaching for a distant mouse over many hours puts real strain on the shoulder. Leave 10-15 cm of free space in front of the keyboard so you can rest your wrists during short breaks.
Your feet should rest flat on the floor, with your knees at roughly a 90-degree angle. If the chair height is correct but your feet don't reach the floor, use a footrest - dangling legs quickly restrict circulation and tire out your thighs.
Soft, diffused light works best - no harsh shadows and no direct light hitting the screen. During the day, take advantage of natural light, but place the screen perpendicular to the window, not facing it. In the evening, switch on a desk lamp that illuminates the keyboard and surface - working in a dark room with a bright screen tires the eyes much faster.
Take a short break every hour: stand up, stretch your back, clench and release your hands a few times. Every 20 minutes, look at something several metres away - this simple 20-20-20 rule noticeably reduces eye strain during long typing sessions.