Whatever brings you joy. It might be a hot bubble bath and a good book. It might be watching a TV show. Doing yoga or exercising. Maybe it's playing video games (Yep, that's me! I love to play World of Warcraft to chill out). Maybe it's scrolling through Facebook posts or watching YouTube or getting a facial.
Make time for you. It's not selfish. Don't feel guilty for carving out some quality alone (or not alone if that is what you need) time. In order to be the best possible you, you have to take care of you! Take 5 minutes if that's all you can do, but do it. Take a full day if you can - you deserve it.
Find your joy. Do your joy.