I use a couple of techniques for different lighting conditions. The one described above by David is the best one to use if you're shooting with the sun behind the subject. Simply meter on the background, transfer the reading to your C330 and then set your flash one stop wider (if your camera is set to f8, set your flash to f5.6). The other technique I use is for when the light is falling across the subject, one half in shadow the other in full sunlight. Take an incident reading towards the light source (the sun?) and set this on your camera. Again, set your flash one stop wider, as in the previous example. This gives you beautiful, well exposed highlights and also picks out the shadows.