When the sun is really harsh, you can still get wonderful portraits by placing your subjects just inside a shady area. This might be just under an umbrella (like my example of these gorgeous siblings), inside a garage door, inside your house door, under the slide at the park, under the light of the first tree, etc. The key is to not position your subject too deep into the shade. You want all of the light that is just behind you to spill softly onto your subjects. This will give even lighting across the face(s) as well as great light in the eyes. (65mm -cropped; F/5.6; ISO 400).
BONUS Lesson: This second photo was also taken in the open shade of a small umbrella on a very bright beach. Here you can actually see just how close they are positioned to the edge of the shade. But I am throwing this in to illustrate leading lines. Your eye naturally goes to the boy first and follows down the line to the sitting girl, but notice how the lines of the table push your eye right back up again. This is a great way to keep your viewer engaged within the image.(55mm; F/5.6; ISO 400)