[Disclaimer: Information only! Do not try this at home. This is not an invitation to engage in this activity or permission from your mom. You're on your own. Unless you've done this a bunch, this is at least a two-person operation. (Sometimes it takes the whole damn family.) Tying a foot up - at least for the first few times - is never, never, ever done on a hard surface, in a confined area, with other horses at liberty in the immediate area or without somebody around who knows what'n hell they're doing.]
Most folks use 1/2" soft-lay Nylon because it's cheap and readily available; 3/4" cotton is not worth the trouble of hunting down. In one end of the rope, tie a loose loop around the horse's neck with a bowline. The knot (bowline) should be hanging free, at about the point of shoulder. If you don't know how to tie a bowline, learn. Walk the horse forward until he steps over the rope with a hind. At this point, the rope should be looped around the horse's neck on one end and between his hind legs on the other, without much slack. The rope should not be between the horse's front legs. (n.b. history buffs: This is probably from whence the cowboy/farrier expression, "You gotta walk the sumbitch across a rope", an expression of relative equine gentleness, originated.)
While one person keeps the horse from wandering off, an accomplice retrieves the end of the rope (which is running between Dobbin's hind legs), takes it forward, runs it through the loop around the horse's neck and back on itself. Immediately after going through the loop, they take a couple of wraps on the line. (Try like hell to keep the rope from touching the horse's hind legs while you're doing this.)
Ease the slack out of the line, while somebody keeps two hands on the wraps. Once Dobbin feels the rope against his foot, he may or may not throw a wall-eyed fit. At any rate, no matter what the horses does, once you get the rope against the foot, it will slide up the bulbs to fetlock. Keep tension on the rope and pull the foot forward. The mechanical advantage offered by the wraps will enable you to hold the foot up. If you keep the slack out of the rope while you're doing this, Dobbin will not rope-burn himself too badly; if you cut him any slack, you'll be doctoring rope burns on a less-than-appreciative patient.
If (usually, when) the horse throws himself, sit on his head and tell him how the cow ate the cabbage for a while, then give him a little slack and make him get up. Repeat as needed.
When he quits fighting the restraint, the farrier can safely shoe him - provided he keeps his hip away from the horse. If the farrier gives the horse something to lay on, he probably will. It's a little out of position to shoe one with a foot tied up, but it's a hell of a lot easier and safer than dodging feet and a whole lot faster than tying one down.