First, make a four cord braid the length you want.
Now put a rubber band around the end so it won't come undone.
Using an ink pen, number the ends of the cords 1,2,3 and 4. Or put a small piece of tape on each end and write the number on the tape.
Hold the braid between your thumb and forefinger so that the braid hangs towards the ground and the loose ends are sticking out above your thumb and finger. Arrange the ends as shown in Fig. A.
Proceed as shown in Fig. B, C, and D.
In Fig. E you will see that lace number 4 goes over number 3 and then goes under the loop created by number 1.
Pull the ends evenly until this knot is just a little snug, but not tight yet.
Does it look like Fig E? If so you are halfway there already!
Take a look at Fig. F now. Grab the #1 lace and bring it to the right around #3 lace and then go under #2 and #3 coming out in the middle of the square as seen in Fig. F. and also marked with a circle in Fig. G.
Repeat using #2 around #4 and then under #3 and #4.
Repeat using #3 around #1 and then under #4 and #1.
Repeat using #4 around #2 and then under #1 and #2.
Fig. H shows how I accomplish this using a pair of curved hemostats pushed in at the center marked by the green circle and out where the #1 lace should enter. Clamp the hemostats onto the #1 lace and pull it right through. (This can also be done just as easily with a lacing needle instead of hemostats.) Proceed to #2 lace.
When you are done, all four ends will be coming out the of the center of the knot from the spot shown in Fig G. Pull everything tight and you are done! I use an awl to alternately work the slack out of the loops and pull on the ends until it's even.
If you look at Fig. L, you will see I do this at both ends of a braided keychain. To do this, start by folding your two pieces of lace in half around a pen or pencil. Now do a turks head knot around the pen. Slide it off the pen and you have a nice loop to put a keying through (see Fig. K). Braid the four ends until you reach the proper length. Do another turk's head, and your keychain is done!