The biggest change for me was getting off of social networking. I always told myself it was a great source of news and articles but the truth was it was mainly junk.
Once that was done I unsubscribed from any e-mail list I was on. As soon as a product marketing e-mail came in I'd find the unsubscribe link. This drastically cut down on the amount of e-mail I got each day and helped me avoid checking it every time something came in.
The only thing my phone alerts me for these days are text messages and real phone calls. Also uninstall slack or your work e-mail app ASAP. I work in a field where there should be no after-hours calls so any e-mail that comes in is likely not an emergency so it can wait until the next business day.
Exercise! I hated running but have taken it up recently because it has a low barrier of entry and can be done basically anywhere at anytime. Since I've started I've actually come to enjoy it a bit because I feel great afterwards.
Read books and/or find a hobby. Mine is woodworking with hand tools. Because I don't use power tools I setup a small work area in my basement and can work at all hours without worrying I'll be keeping someone awake in the house. Most of the stuff I make is shit but it's still a great way to really get yourself in "the zone" and stop thinking about everything else going on in life.