To maintain good posture while sitting at a desk, ensure your feet are flat on the floor and your knees form a 90-degree angle. Keep your back straight, support the upper back, and maintain the natural curve of your lower back. Adjust your chair so that your elbows are at a 90-degree angle and your forearms are parallel to the desk. Position your monitor at eye level to avoid neck strain and relax your shoulders. Keep your wrists straight and aligned with your forearms, and consider using a footrest if your feet don’t touch the floor for proper support. Remember to take regular breaks to stretch and move around, which helps maintain good posture and reduce strain.