It goes without saying that safety is important - read the instructions on the box, keep the fireworks in closed boxes and wear protective clothing, gloves and goggles. You can't control the direction fireworks go off in, which is why it's important to have the fireworks down-wind of your audience. Make sure that any fall-out is not going to land on cars or inflammable structures, and never stand over a lit firework - the saying "light the blue touch-paper and retire" is spot on.
Vary the height of the fireworks: aerial shells that you fire out of mortar tubes reach between 200 and 1,200 feet into the sky (the bigger they are the higher they go), whereas Roman Candles and Cakes, which are a series of little tubes put together, fire at a lower height, about 100 feet.
Your finale should always be about volume, with lots of material being fired up. You get the best response from very, very intense bursts, ie letting off a lot of fireworks in a very short space of time. Don't go for drawn-out displays where you try to make a small amount of fireworks cover a long period of time.
Certain fireworks are only available to professionals, but get as good a selection as you can afford. Most fireworks sold in local shops are Chinese, but lots of countries make them and they each have different characteristics. The Italian and German fireworks are very, very precise, the Spanish ones are very noisy and the Chinese tend to have the most volume for the least amount of money. It's great finding out some of the names - "Bees Chasing Pollen", "Poisonous Spiders", and my personal favourite, "Laugh With Joy".
John Wassell is pyrotechnics director at Walk the Plank (0161-873 7350), putting on year-round fireworks displays