The ability to erase your photos is one of the major advantages of a digital camera. You’d be mad not to use this to the fullest extent!
Take MANY more shots than you think you need, and then erase those that aren’t right.
Every half an hour, go back through your most recent photos erase any that don’t make the grade, or you have better versions of.
Because you’ll be erasing often you can just keep the ‘best of the best’. Erasing often also ensures you don’t need a large memory card, as it will not be storing your not-so-perfect images.
If you’re always pressed for time, you can either invest in a larger memory card, or copy your images to another storage device like a laptop or card storage unit until a later point.
This is also a huge tip when photographing groups. With such a large number of people, there always seems to be someone blinking, or looking the other way. Having a large number of shots means you can pick the best of them to keep.