Take a Tripod...even if you have one of the fancy cameras that can shoot in the dark. You will WANT a long shutter speed to show the motion of fireworks, like 15-30 seconds! Unless you are superhuman and have no heart beat, you can't hand hold it.
Know how to use Manual Mode on your camera. You will want to change the settings the camera thinks are the exposure. (If you don't have a manual mode, play with night mode or see if you have a 'fireworks mode') The great thing about digital is that you can play and check. The hard part is that we only have one, maybe two, nights of practice. Looking back at some images from the last couple years, I usually shoot at ISO 100, f8 and a 30 second exposure. That can all change of course, but it is a starting point.
*Keep in mind that your LCD screen will look brighter than is actually is because it is so dark outside...so if it looks perfect, it may not be bright enough of an exposure.*
Once you get things down, think also how you can take photos that may be different than others, or that show context or another element of interest. (The last two have a flash off camera to add in some light.) Search the internet for other images to see how other people shoot..then try something different.
Oh, and don't forget to have fun...not just with your camera but with other people that you may be sitting with. Don't ignore them TOO much.