Step 1: Supplies
There isn't much to it!
Step 2: Wrap Your Hand
Decide how big you want your pom pom before you get started. Your option is to wrap 2, 3, or 4 fingers (I discourage 1 as it will be harder to work with - us a fork if you want a really small pom pom). You could also wrap your whole hand or wrist if you want a big pom pom. Two fingers will give you a good normal size pom pom.
Hold the end of the yarn between your fingers. Now just keep wrapping your fingers until it is as thick as you want your pom pom. Try not to wrap really tight. You aren't going to leave the yarn on your fingers for yarn, but try not to hurt them.
When you've wrapped them enough, cut the yarn.
Step 3: Tie and Cut
Carefully slip the yarn off your fingers. As long as you don't keep handling it, your yarn bundle should stay together.
Take a separate piece of yarn and wrap it around your bundle. Tie it into a knot. The knot is going to want to stretch, but don't let it. Wrap the yarn around the back of the pom pom and tie it two more times (I did 3 knots, but you can just do 2 on one side and leave it at that as well).
Once it is tied up tight, cut open all the loops.
Finish your pom pom by trimming all the yarn to the same length. I did only a little bit of trimming and the pom pom ended up being the same size as the fingers I wrapped. If you want a fuller pom pom, you can trim it down smaller.
Step 4: Done
And that's it! This is a nice way to do it as you need very few supplies and can still make the pom poms a few different sizes.