I begin cooling my horse out on the road by walking the last half-mile-unless there's a bitter wind blowing; in that case I keep up my conditioning trot right to the barn because cooling in the wind will chill him and stiffen his muscles.
Inside, I loosen his girth (leaving the saddle on so circulation returns gradually to under-saddle areas), pick out his feet, remove my helmet and half-chaps, and (in cold weather) button my overshirt and zip up my coat as I cool down.
Then I take his saddle off and brush matted areas of his coat with a curry--separating the hairs helps him dry faster--and put him in the stall to roll.
As I work, I monitor his temperature with a hand on his chest (still damp, like his neck and flank area, though the rest of him is nearly dry by now). When he feels barely warmer than usual, I put on his old hand-spun wool cooler: a not-too-heavy blanket, fastened in front with a utility clamp and secured around his belly with a surcingle, that wicks moisture away from his full coat. I give him fresh water and hay, then go in to (if it's evening) feed my dog and three cats, eat my dinner, and wash up.
When my horse is dry, in a couple of hours, I take off the cooler and give him and the other horses their grain-variable mealtimes aren't a problem because they have free-choice hay and roughage is the most important part of their diet. As he eats, I brush him thoroughly to fluff his coat when he's turned out after supper.
Warming weather makes cool-down easier, even before my horse gets his pre-competition clip in April. In spring I sponge off (with warm water), scrape, and towel-dry his sweatiest areas, then leave him in the barn for up to an hour with his cooler on. Unless the weather is nasty, he can go out and finish drying in the sun when his pulse is about 60.
In summer I walk the last half-mile home, rinse him with the hose (which makes him easier to clean later), scrape him as dry as I can and turn him out to roll.
Dr. Heather Hoyns is a busy equine practitioner at the Kedron Valley Veterinary Clinic (near Vermont's Ascutney Mountain ski resort), and a serious endurance competitor. She conditions through Vermont's famous winters, sometimes riding after dark in reflective clothing; her horses are unclipped to enable them to live outdoors (with run-in sheds) in most weather conditions. Here's the system she uses to make sure, with a minimum of fuss, that after a ride her horse is dry and ready to re-join his paddock-mates outside.