How do you format an SD card?

If it's new, don't format it unless you have to. Try it out first and make sure you get the correct number of shots for your camera's megapixels. It's better to delete the photos while the SD card is in your camera, rather than format it in your pc. Some SD cards are pre-formatted by the manufacturer, and I've found that if I format this one particular brand, I get a lesser number of shots!