Backlight is best shot in manual mode. (In fact, it is one of the best reasons to learn to use it.)
Use spot metering or take your meter readings with only the face in your frame. Backlight will easily trick your camera’s light meter and cause an underexposed photo.
Haze and sunflare can easily happen with back light. They are the result of light streaming directly into your lens.
Encourage haze and sunflare by including the sun in your frame or placing the sun directly behind your subject.
Avoid haze and sunflare by keeping the sun out of your frame and placing it slightly to the left or right of your subject instead of directly behind them.
Mid-day sunlight is also best shot on manual mode. (Anytime you are shooting shadows and highlights, manual should be your first choice!)
Position yourself so that your subject is looking into their own shadow (you can use some of the tips for back light here) to keep nice, even lighting on the face and avoid “raccoon eyes” from overhead sun.
Having your subject look away from the camera can also be a great way to minimize the distraction of the mid-day sun.
Avoid bright blown-out highlights and deep shadows on the face. Not only are they distracting, but they are hard to post-process.