I use these wristlets, because they restrict my circulation less than other wrist restraints. They are good where there is a lot of pull on the wrist, like suspension or tight hogtie. They are made of hardware-store components, and don't attract as many embarassing questions as special leather wrist ties.

1. Wrap the wrist with a thick athletic sock. Tack it in place with a short piece of duct tape, fabric to fabric.
2. Wrap the wrist with about 1-1/2 turns of strapping, about 1 to 1-1/4 inch in width; I use cotton, the friction is good. Have a quick-link (screw-closable chain link, from the hardware store) about 1/3 of the way in from one end of the strapping. Make sure the 1/3 end of the strapping is on the OUTSIDE layer, otherwise it won't be secure. Position the quick link on the inside of the wrist. Tack the strapping in place with a short length of duct tape.
3. Wrap the strapping/sock with 1-1/2 layers of duct tape. Bend the duct tape down so it doesn't interfere with the operation of the screw closure of the quicklink. When you are in bondage, I doubt that you will be able to unwrap the end of the duct tape; but if you want to be extra secure, wrap a second layer of duct tape, and fold the ends back so they make a sticky-to-sticky bond where they meet.
4. You're done. You can put extra hardware on; a swivel can be good. Hardware store swivels can support my full weight with no problem. Swivel plus padlock works well. You can also use the cinch-noose of Super-hogtie on the quick links; just go around through the 2 quick-links twice as if it were Super-hogtie's wrist loops. This makes a convenient way to get into a hogtie.