* Keep a bucket of water or the hose handy. It's not hard to do. It doesn't spoil the fun. But you can use it to douse duds or prevent small fires from getting big.
* Use safety glasses if you are setting off fireworks. It can't hurt but it could save your eyes. The danger is not just from objects shooting in your face but also from particles that come off regular fireworks.
* Don't be an idiot. Don't point fireworks at others. Don't let small children play with sparklers. Don't drink and get silly.