I have two answers...
A short answer is ... put the camera into Tv mode, dial it to f/4, and use a long-ish focal length (avoid wide-angle) and keep the background at some distance behind your subjects. Light shade really helps.
And now for the longer answer...
Before the days when light meters were built into cameras, if you didn't happen to own a hand-held light meter, you had to memorize some common exposures. The "Sunny 16" exposure is a rule/guideline designed to work when shooting outdoors in mid-day full sun.
It says that if you set the f-stop (aperture) to f/16, then the shutter speed should be set to the inverse of the ISO speed. In other words if you use the base ISO of 100 on the camera, then you'd set the shutter speed to 1/100th. At ISO 400... you'd set the shutter speed to 1/400th. You get the idea.
However... full "mid day" outdoor sun is miserable if you want good looking images. The bright sun creates rather extreme shadows. If I have to shoot outdoors, I always use flash. I set the flash exposure compensation to "-1" when causes the flash to behave as "fill" light. That means I want the flash to fire at about half the power needed to take over and be the primary light source. This means the sun will still be the primary light source... but the flash will fill in the shadows so they are about half as dark as they would otherwise have been and you get images that look a bit nicer.
This assumes you have an external flash ... fairly powerful. E.g. a Canon Speedlite 430EX II, a 580EX II, or a 600EX-RT. The built-in pop-up flash will not be nearly strong enough unless your subject is only about 5' away.
SO.... the alternative is to get those subjects out of the bright sun. If you can shoot them in "light shade" then you'd open up the aperture by 1 stop (e.g. f/11 instead of f/16). Try to avoid dappled light (which doesn't look very appealing). Medium shadow is 2 stops (f/8), and very dense shadows is about 3 stops. This also works for clouds. If it's a partly cloudy day, you get a better looking shot when there's a cloud blocking the full power of the sun than you get when you have open sky.
If you want blurred backgrounds (always nice for portraits) then you'll want to drop the aperture down to around f/4 or f/2.8 (I prefer f/4 most of the time on my full frame camera... on a crop frame I might go a bit lower). That means you need to drop 4-5 stops. You could do that by increasing the shutter speed IF you aren't using any flash (if you are using flash then it gets tricky to shoot faster than the flash-sync speed of the camera... most Canon DSLRs have a flash sync speed of around 1/200th... some are 1/160th... some are 1/250th.) The flash has to go into "high speed sync" mode for this (and have enough power). So a bit of light shade makes this much easier because you don't necessarily need flash at all.
HOWEVER... if you're in light shade... make sure you don't have a bright background (if you're in the shade of a tree but the camera sees a background which is in full sun then you'll get an over-exposed background when your subjects are correctly exposed and that's no good... you'd need flash to fix that.)
Tim Campbell
5D III, 5D IV, 60Da