This interview – Why So Many Smart People Aren’t Happy – makes a few good points. Some that I find particularly useful:
– meaning, belonging, and autonomy are key ingredients to happiness
– attitude also makes a big difference, specifically being scarcity-minded (e.g. either I succeed or someone else does, we can’t both win) or abundance-minded (e.g. there’s room for everyone to grow)
– orient your progress around processes, not peaks, for every peak is a false peak