One of the most common difficulties encountered by learning photographers when shooting portraits outdoors is backlight. A lot of them don't know how to deal with this type of situation, so it's probably a good idea to come to their aid.
Dealing with this issue starts with one important step: setting the camera to Manual mode. It's not that we don't want you to use the automatic and semi-automatic settings on your camera, but with backlighting, 99% of digital cameras get it wrong. That's because the background is very bright and all cameras are programmed to compensate for that and avoid overexposure. The result in this case will be a well exposed background and a very underexposed portrait.
With that said, shift to M mode and have no fear. The next step is to take a metering. Do that by setting the aperture to a value of f8 and move close enough to frame only your subject's face. You'll most likely end up with a reading that sounds very unrealistic for the lighting conditions, but trust your camera's meter and shoot anyway.
The idea with shooting portraits in backlight is to have the face properly exposed. You can do that even in broad daylight with the full power of the sun behind the subject. It's not the background that interests you, it’s the even light on the face of your model. Believe it or not, using this technique, you'll be able to take great looking, well lit portrait photography in harsh lighting conditions that you wouldn't even consider taking out your camera.
(Success Tip:Take better photos with this simple deck of cards)
Here's Bryan Peterson demonstrating this technique in a video from Adorama TV.