This year I decided to take an updated version of my fireworks shot.  I didn't want to really "stage" it because I didn't want to distract my kids from enjoying the show.  I also didn't want to use much equipment because we were going to be at a friend's house and I didn't want to carry it (Nor did I want to set it all up in the middle of a party.)  So, the task became, "How do I get a cool shot with a minimal amount of equipment?"
First, I set up the tripod behind the chair that my daughter was sitting in and extended the legs out so that I could get the camera low.  I moved around a bit until I felt I had a good composition for getting Mackenzie and the fireworks both in the frame.
Next, I set the ISO at 800, the aperture at f10 and the shutter speed at 2 seconds.  
Why these settings?  
I knew that I would be using manual flash and I usually shoot at ISO 800 when I use manual flash.  I'm just used to it, is all.  
The aperture is at 10 because I want a good depth of field.  Why?  Because I had to focus manually since it was too dark for the camera to do it.  I wanted room for error.
Finally, the shutter speed was just trial and error.  By this time the fireworks have started and I am trying different speeds.  Two seconds seemed about right.
So, now I have my camera set and ready to go and I start taking pictures, trying to time it so I get a good spread of fireworks.
Now the tricky part.  I press the shutter and during the 2 second exposure I run over to the side and pop the flash on Mackenzie.
The other guests are looking at me like I'm nuts but I know what I'm doing.  Two seconds is plenty of time to take a few steps and pop the flash.  I do that about 10 times total.
When it's all done I end up with two good pictures.  One has a great sky full of fireworks but Mackenzie is dark because my flash had powered off.  The other has a great shot of Mackenzie but a poor fireworks display.  All that's left is to combine the two in Photoshop and another fireworks picture is ready to go!