If you, like me, spend hours a day using your eyes for short range focus i.e. reading and looking at computer screens, it's a good idea to take regular breaks to look outside to the natural world.
Take 2 minute breaks throughout your day to gaze at a cloud, or a natural object in the distance. This naturally gives you eyes a break and a chance to relax into long range focus. Add a deep breath or three and a stretch and you can relax your whole body.