Improper use of a mouse and keyboard can cause musculoskeletal issues like carpal tunnel syndrome and tennis elbow due to stress and impact on the wrists, elbows, shoulders, and neck. To prevent these issues, the document recommends using an ergonomic keyboard tray that allows adjusting the keyboard height to be level with arm rests and close to the body, with the keyboard flat or tilted away, and an ergonomic split keyboard and mouse to maintain proper form and reduce tension.