Ashley Book Of Knots # 792 makes a nice lanyard knot. Shown in red in the photo on the left it is larger than the diamond/lanyard knot on the left. You can see the pattern when it is tied in two colors.
I normally tie this knot using the two ends of one cord. I used the two colors to make it easier to show the steps in tying the knot.
Make an overhand knot.
Tie a second overhand knot beneath the first.
Place dowel or pencil over knot and bring left hand knot over pencil and through bight on upper right....
Turn the knot over and bring same end down to the right across knot (left hand image)
Bring the left hand (red) end over and through the bight on the upper right.
turn the knot over and bring the same end down to the right through the bight over the pencil
Remove the pencil and slightly tighten the knot. Locate the top center of the knot - between the crossings of the red and blue cords.
Bring the blue end up through the center of the knot (notice how the blue cord crosses over the red cord coming up from the seizing)
Bring the red end through the center of the knot (crossing over the blue cord)
The knot is complete - now tighten.