I've been trying to photograph fireworks for 20-something years, and mostly it has been a total failure. That's not a big deal in the digital days, but it sure was expensive in the film days. When I lived in the Cleveland suburbs, I had a great view from home for the yearly Independence Day show in town, and I got lucky a few times there. I was less lucky with Cedar Point fireworks, but I also didn't see those as often (because the park was a zoo those days). Now, my front door is 10,348 feet from the place they launch fireworks every night for Magic Kingdom at Walt Disney World. You might say that there's plenty of time to practice.
So a couple of times a year, I bust out the tripod and put a camera on it, usually for the new year and Independence Day, and I rattle off a bunch of shots and hope one doesn't suck. The timing is still hard to get right, even if you know what to expect, but at least I can say consistently what the best exposure is. It's f/13 at 2.5 seconds (ISO 100). Actually, the time can vary depending on how much streaky you want, but for my tastes, you can't beat 2.5 seconds. If you stop down any less, the color tends to wash out, and if you stop down any more, it just looks underexposed.
There is also some luck in how the show is performed. A bunch of bursts in the same spot, or in your line of sight, just result in a big bright blur of light. Nothing you can do about that, but if it's a good show, they probably spread out the stuff. The big special holiday shows at Magic Kingdom include shells launched from all around the park, so the finale is pretty well spread out. In my case, I do get some overlap during the finale, but it generally looks pretty great.