AMERICA!
Dos: BBQ, drink beer, listen to George M. Cohan, punch a nazi, drink lots of water, have more beer, punch more Nazis, rescue a bold eagle, go to a city fireworks display if that's your thing, remember that American history is full of awful violent moments of exploited people build it.
Don'ts: Shot guns, ignore local fire work laws, be a racist shit, listen to Fox News, light fireworks well holding them, drink Pabst, try and rewrite history to fit a version of events the make you feel comfortable.
Things you probably shouldn't do but are kind of hilarious: Act super-extra Americany towards all your British friends in a polite, fun, and slightly over the top way.
Stay Hydrated, Keep Dreaming.