Just so you know, I suck at taking pictures of fireworks.
I can't offer any tips on taking them and the ones I have read have left me still guessing. Granted, I only get once a year to practice and I've only had my dSLR for two years so I'm probably being a bit harsh on myself. Here are this years efforts. They are composites of several shots put together with photoshop. I wish my foreground was a bit more interesting but that's how it worked out. Some are pretty good but it's tricky getting something great.