Midday is the worst time to photograph, especially if your shooting people, but sometimes, it's unavoidable. Luckily, it's easy to use your fill flash to dramatically improve the lighting conditions you've been forced to work with. Fill flash also helps when you have extensively back-lit subjects, like people in front of a window. The fill flash will bring light to the areas that aren't catching the natural light, eliminating dark shadows on objects and faces. Use your DSLR to view your results immediately, so you get a sense of what's working at what isn't, because it is possible to overdo the fill flash. Read more at Digital Photography School.