So it sounds like I'm doing photos of my younger brother and his date for prom at his high school. They will most likely be done outdoors in a nearby park, where I can choose from sunny to shade and in between. There is a very nice rock garden with a stream that I will most probably use as a background. What should I keep in mind as far as technical items, such as composition, positioning, and exposure? I don't have any professional studio equipment, like lights or anything, and I've only got the built-in flash, so I'm going to try to make the most of ambient light. Of course I will be shooting in RAW, so I can compensate for any bad exposures. It is not paid, but rather I'm doing it as a favor for my brother and parents. This would be next weekend. Any help is appreciated. Thanks!