To improve flexibility in muscles and joints, the technique of static stretching can be highly effective. This involves gently stretching a muscle to its farthest point and holding that position for 15 to 60 seconds. Static stretching enhances flexibility by lengthening the muscle fibers and improving range of motion. Additionally, incorporating dynamics and yoga can help maintain flexibility over time. It's important to perform stretching routines consistently and after warming up the muscles to prevent injury.