Personal message from Mr. Fowler...
Start with two pieces of rope that are close in diameter. We'll call them rope A and rope B for ease in describing this process.
Hold the end of rope A in your left hand and the end of rope B in your right hand.
Cross rope A over rope B to form an X.
Wrap A once to the right around B, just like the first step in tying a bow in your shoelace. A is now sticking out to the right and B is to the left.
Cross A over B again, forming another X.
Wrap A once to the left around B.
Pull on the free ends to tighten the knot.