First off, if you can get away from usual environments where others are stressed (maybe to a branch of the local, county, library you've never been to before?) that helps me. So does taking a walk every now and then and using the time to think or plan. I get some of my best ideas of how to do something or how to understand something when I'm walking (and some people get them in the shower, taking a nice shower and maybe a nap might help?).