Go on a trip, and do something physical outside. Ideally, combine the two--I went on a very long bicycle tour, but a running/kayak/canoe/hiking trip would also

Go on a trip, and do something physical outside. Ideally, combine the two--I went on a very long bicycle tour, but a running/kayak/canoe/hiking trip would also work. Bonus points for making the trip itself an achievement, but even if all you get is some clear-headed thinking in nature you should be fine.