One of the biggest issues that I have come across is how to deal with less than ideal lighting situations, especially direct sunlight. Direct sunlight creates a bunch of unflattering shadows on your face. Over exposes details so you have odd highlights and a multitude of other problems that just don't add up to a good picture! Here are a few tips on how to deal with that: 1. If you can, photography in the shade. Put people under a tree or under the shade of a building if it is at all possible. Granted this is not always possible. Sometimes you can't change the position you are taking the picture from and you just have to deal with it.
2. Another great way to deal with the sun is to use your flash to even out the shadows. Fill-Flash will fill in the shadows and even out the tones on your subject.
3. If you have one, another really good option is a reflector. You can use some different DIY reflectors on the fly to reflect the sun back at you. You can make a reflector if you want to keep it really inexpensive. (Glueing aluminum foil to poster board). Most reflectors are affordable and easier to transport. If you have photos coming up or you are in a pinch then the DIY method is a good one.