The colts stay close to the barn after weaning and are fed their grain inside a stall once a day, to get used to the confinements and activity going on around them.
Otherwise they live outside with a shed for shelter (that they never use). During the next summer they gradually get introduced to the other young horses and spend their next years in a 160 acre hill pasture, where they learn to paw through ice, run on steep and slippery ground, and behave proper around horses higher on the pecking order. Occasional they all get haltered out in the pasture to get wormed and their hooves trimmed. 
When they are ready for saddle training, one at a time gets introduced to the "saddle horse bunch" and life around the barn and people again, gets tied up and grained and worked with or ridden usually at least twice a week until sold, summer or winter.

Our goal is to have a calm and sensitive, fearless horse that has the ability to adjust to anybody's style of riding or handling, and that deals with confusion by patiently trying out different responses to any given request, without getting upset.
We trailer them to the arena in town, ride them alone in the hills or in groups, take them to move cattle at our place or the neighbor's.
They become familiar with going through boggy spots, steep or slippery trails, going through thick bush without banging the rider's knee, going across bridges, through coulees etc. etc. 
They also become familiar with other horses charging by, leaving them behind, and the all around excitement of moving cattle. We sometimes move 240 cows and their calves, which often end up running either towards home, or away from where they are supposed to go, causing riders to charge around, dogs pinching cattle and causing a ruckus, riders might yell or wave at the cattle, trying to get them to turn , etc. etc. 

Later that summer we take one horse at a time and ride them through the pasture where loose horses come over to visit, then turn tail and race off. We ride them on very windy days, or in cold weather and rain! We lead other horses while riding them, swing ropes, put coats on, drop things from the saddle. Some of them we take to the local fair, some to clinics, some to brandings to pull calves to the fire.
All of this increases their trust in people and makes them feel at home in a people's world. 
And they know how to patiently stand tied up at the trailer or hitching rail, or just stand around during a ride, waiting for cows to settle or the last ones to get through the gate. 
Most important to us, our horses can be ridden on a fairly loose rein, no need to "keep them in gait" or "ride the brakes" all the time, and will stand for mounting even if everybody else keeps on going after closing a gate.