If national news gets you down, do something that helps locally.
Instead of insulting someone for their opinion, ask a few questions to try to understand how they came to form that opinion.
Instead of talking on your phone while talking to a server/barista/bartender/customer service representative, ask the server/barista/bartender/customer service representative how they’re doing. Actually, in general, if you treat people like people instead of like tasks, robots, or soulless Internet avatars, you might find you have way more common ground than you assumed, and even if you don’t, you might discover that that person, although having different opinions than you on many subjects, is still a pretty decent human being who, like you, likes beer and/or likes bicycles and/or likes baseball and/or likes Star Wars and/or has kids they’re really proud of and/or has a parent or grandparent dying of cancer and deep down, probably doesn’t ever want bad things to happen to people, but, you know, the world is a complicated place. And maybe if we all tried listening instead of picking teams and bickering, we might be able to fix some shit.