Do less.
That's pretty much it but this is what has worked for me.
Remove any commitments you can outside of work. Go home at a reasonable hour. Leave plenty of time for rest and relaxation. Don't check email outside of work. It's ok and important to do nothing and waste time. If you're like me, you have this feeling that you always need to be doing something. That is very detrimental.
Most importantly, your body will tell you when you are stressed. Listen to the signals and take a break. Small breaks during the day are just as important as longer breaks at night and weekends.