I've found myself repeatedly doing a tutorial for how to make tassels, so I decided to create an official post for how to make these little guys. Mostly for my sanity, so I can just link to this whenever I need to include it in a pattern. :)
This method is super easy, and I use it for basically all of my tassels.
To start, start running yarn around your hand until it's the thickness you'd like. For this particular tassel I wrapped it around my hand 20 times. Then you'll cut the yarn at the bottom of your hand.
Slip the wrapped yarn off your hand and run a long strand through the top of your bunch of yarn. Sometimes I tie a knot on the top, other times I don't. It depends on the pattern.
Then wrap a 15-inch or so piece of yarn around the outside of your bunch of yarn about an inch from the top. Tie a knot, then wrap both the ends to the other side and tie a double knot.
The above photo is what it will look like. Then you will take those ends that you just double-knotted along with a yarn needle and draw them through what you just wrapped so they aren't sticking out.
Next, cut the ends of your tassel, and shape them up so all the ends are even.
Then you've got yourself an easy-peasy tassel! Go you!