"Rejoice in the Lord always," was St. Paul's advice, even when he was in prison. How did he manage to do that? I think he told us when he told the Philippians what to think about: whatever is pure, whatever is lovely, whatever is admirable, whatever is excellent or praiseworthy. Think about these things, he said, and you will have peace (Phil 4:3-9).
It is advice I have tried to follow. For example, I listen to a number of different radio stations for news and music, but my default choice now is a Christian praise music station. When I need the weather or traffic report, I switch to a news station, but then I switch back. If my mood is down or depressed, Christian music lifts me back up again.
The Psalms have always been my personal go-to spot for a written pick-me-up. It seems to me that many of them begin with "woe is me" and end up praising God (see Psalms 69 and 71 for example). They never fail to lift me up from my personal "pity party".
What about you? What picks you up when you are down? What helps you to "rejoice in the Lord always"