If I have the time, I go backpacking. No phone, no music, maaaaybe a book. Then just walk in the woods until I'm tired. Cook a simple dinner. Go to sleep at sunset - easy when you have nothing to distract you. Sleep until first light, then roll over and sleep some more. Break camp. Return to walking in the woods. Repeat until you feel at peace. May take up to 6 months or more for full effect.
I also like to follow the advice about gumption from Zen and the Art of Motorcycle Maintenance. I'm currently in the process of reproducing the entire quote below onto a couple pieces of plywood to hang in my shed.