It’s a good idea to use a lens hood to reduce this flare as much as possible. Finger marks and dirt will increase the chance of flare which softens images and may create odd patches of light. With a strong backlight or sidelight it’s important that the front of your lens is really clean. You may have to walk back some distance from your subject to gain the most of the compression effect.
If you have a longer telephoto zoom lens, try turning the zoom to cut the distance between the subject and the background. This will give the most flattering results. Even if you have a standard kit lens, try zooming to the longest setting then walk back from your subject. Portrait images look best when you use a longer lens. The longer zoom setting flattens facial features for a more pleasing result. If you zoom in to your subject, even walking away from them a little if necessary, the results are more flattering. When you want to take portrait photos in early autumn light, the key is to capture your subject in the best possible way. The coming of colder nights also mean there's a greater chance of fog forming in the morning - so get out and capture photos and movies of misty city or countryside before any sun burns it off.
The lower elevation of the sun in the time means light is often warm and soft - great for shooting photos throughout the day. The shift towards the colours of autumn means that now is a great time to take a walk with your camera.