Photographing fireworks is one of my favorite activities.  As in other forms photography, preparation is critical to success:  you have to scout the location, set up the tripod in a good spot, adjust the camera settings for the expected conditions, aim the camera at the right angle, and mentally prepare yourself to adjust all these things on the fly as reality dictates.  And after all that, you still have to nail the timing of your shots, perhaps moreso than any other genre of photography (especially if you're using a 2-second delay).