one thing for me, was to realize that whatever is happening, its not about "me"
i think sometimes we internalize situations and make it about "us", and while we do indeed cause our own stressful situations sometimes, usually things are in motion (work, poliics, environment) that have really nothing to do with us and internalizing it, as if we are "100% responsible for it" can make one more stressed than it should be
another bad situation to be in is, being responsible but not "in charge", meaning one gets blamed but is powerless to fix the situation (work), then in those cases again, its better to not internalize because in a lot of those cases its politics or bad general management etc... better to see the big picture and put things into perspective...
then even if something was "100% our fault" then just take it as a learning experience "debugging reality", we can do everything right and still completely fail, and that is normal... better to learn and move on (easier said than done, i know)
at least for me, this kind of thinking helped alot with overcoming stress