I’ve been reading a great book by Dale Carnegie, How to Stop Worrying and Start Living. Originally published in 1944 it’s amazing how the key points still apply.
Rule 1: Keep busy. The worried person must lose himself in action, lest he wither in despair.
Being busy has always had a good effect on my outlook on life. Luckily these days I have been very busy. I’d add to this that exercise is key as well. Moderate exercise is the miracle cure that people often overlook.