This is a small but versatile knot. It's so versatile, in fact, that there's more than one way to tie it. Here's the easiest.
Step 1: Loop counterclockwise Loop the end of the rope counterclockwise around the object you are hitching to (let's say a pole) and cross it over the remaining length of rope.
Step 2: Make another loop Make another counterclockwise loop around the pole, but this time pass the end of the rope through the loop you've just formed (between the now two strands of rope looping around the pole).
Step 3: Tighten knot Pull at both ends to tighten the knot.
FACT: A hitch is a knot that is tied to an object; a lashing knot ties two objects together.