Setting boundaries is a critical skill toward reclaiming our lives. There are spatial boundaries (such as a closed door) and time boundaries. If there are no boundaries, people and activities leap onto our plate and into our lives. Here are some ways to create TIME boundaries... the most scarce commodity on Planet Earth.
In the moment
Take mini-breaks and just breathe. Then return to the work at hand. Go to meetings early so you can relax. Pause between tasks. Practice mindfulness. DO one thing at a time. If you are eating —eat. Don't read.
Come early and create ritual at work. I get my desk ordered. Review the day. Set aside regular planning time. Don't work during lunch (that is, IF you take lunch). Take a power nap. Ten minutes works wonders. Make an appointment for yourself. Put YOU on the calendar for whatever is important to your well-being.