Tie it on a round object first. Then slip it on the knife and tighten the runs. The tightening is harder than the tying.
Here is a link that really explains how one is formed. It looks scary at first, but read through the instructions and all of a sudden the light will come on.
If you make a tying jig from a piece of 1" PVC and use cribbage pegs, the knotting will really be easy.
Here is a super tip on making a "tying pony" jig :
Take a piece of 1X6 about 20-24" long. Drill a hole near the end that will fit a piece of 1" dowel. Glue a 6" long piece of dowel in the hole. Take a 12-18" piece of 1" PVC pipe and make a tying jig like the one in the link below. Sit on the board with the dowel between your knees and put the PVC jig on the dowel. You can now quickly and easily tie the knot by turning the PVC as you go over and under the bights. Make a PVC jig for each knot size you tie.....5X3, 7X4, etc.
You can shape the board in sort of a dulcimer shape - to fit your legs and butt , and round the edges for a really nice pony.
A "lacing tip" can also make the task easier. The Perma-Lok needle tips are the best. They can be screwed on cord or lace.
You can just use super glue to make the last 3" of the cord hard all by itself. Stretch the cord tight by putting one end in a vise and tying the cord to something to keep it taught. Apply super glue to the 4" section at the vise. Allow to dry completely, then remove from the vise. Cut the end of with a sharp knife at an angle....instant lacing tip.
For a small object, like a knife handle, a turks head should be kept to 3 or 4 leads. Five bights by three leads works as a good starting point. Once you do one that looks good, use that number of bights and leads on future knives with the same cord type.
http://www.folsoms.net/knots/tejay/index.htm