Bright sunshine, (not so) Perfect for photos!
When I take photos of families, they will often be disappointed if it is cloudy when they arrive. In fact, overcast days can be very good for beautiful soft portraits, and taking photos in full sun causes a number of problems. For a start, the photos can have harsh contrasts with blown out highlights and heavy shadows.
Sun in front - not great
When I had my first (very simple) camera as a child, I remember being told to take photos with the sun behind me so that the subjects would not be in shade.
This causes a few problems though. Your subject(s) will be squinting into the sun and have harsh shadows under their eyes and nose. Other parts of their face might be too bright. Overall, this does not tend to make for very flattering photos.
You can make this work, for example if your subject is wearing sunglasses and looking right into the sun.
Sun Behind - Better
If you really can't get out of the sun, you can try moving so the sun is behind your subject(s). You will need to change settings on your camera to make sure the face is bright enough.
You will get a bright rim of light around your subject's hair and the background might be blown out.
However, your subject will not be squinting and the light on their face will be a lot softer and not have harsh shadows.
Find some shade!
Even better is if you can find some shade. Not all shade is the same, so look for somewhere that isn't too dark and provides even shade. Dappled light causes its own problems with random highlights. In open even shade, you can get beautiful soft light on a bright sunny day.
If you can't find trees, buildings, etc, you could also make your own shade by having someone hold up an umbrella or even a bed sheet.
Anything else I can do?
Yes. You could also use a reflector or fill flash, but this will be covered at a later stage!