1. Take a candlelit bath or shower, and listen to some soothing music while you're in there.
2. Download the OMG. I Can Meditate! app and play around with it a bit to see if it's for you.
3. Start following a bunch of dogs on Instagram.
4. Chill in a restorative yoga pose for a bit.
5. Buy an adult coloring book, and try filling in a page or two to see how you like it.
The book above is especially useful for helping you feel a little bit more calm, but really, any coloring book can do the trick. It's all about getting into a meditative state of mind, so you're not thinking about all the things that are stressing you out.
Find some great ones, including the one above, here.