Make sure nothing behind your subject is going to cause giggles later. Buy the right speed of film. Check out the lighting and amount of movement you are expecting, and buy your film accordingly. The faster the film, the more sensitive to light it will be. When photographing scenery or a panorama, try to include an object in the foreground to add to the sense of depth.
Full sun makes people squint and causes sharp shadows.
While no one wants a rainy day outside, don't curse the clouds that temper the harshness of the sun. Keep your camera handy. Make the most of your flash. Always remember to ask before using the flash in a museum, performance, concert or other sensitive location. But for other indoor events, the flash can make the difference between an unidentifiable blob and a clear picture of your aunt.