This is my own tutorial on how to make yarn falls the simple way. They are cheaper and easier to make then synthetic dread falls. the ones i made are only a set of 2. You can do a set of 2 for pigtails to make a fuller look.
Extra tip: If you have short thin hair like i do. Its a better idea not to use so much yarn because it will way your had down and it will feel like someone is pulling on your hair all day. If you have long thick hair, your falls should be thicker and longer.
Start by cutting your yarn. Choose a length you want and dubble it. If you don't dubble the length, it will be shorter than you intended. Make sure you cut enough yarn to cover your hair. When you are done. Take a hair tie, and tie it in the middle of the yarn. You have just completed your first yarn fall. If you wish, you can make 2. I only make one because my hair is short and thin.
When you have completed your falls, trim them to make them the same length or keep them the the way they are. The best way to put them in is if your hair is in a bun. If you have your hair in a regular pony tail they will show.
Ham it up a bit with some beads, scrap fabric, rexlace(the stuff you make key chain lanyards out off.) Rexlace, is a technical term used for thin, flat, plastic string. You can pick up a variety pack of colors from wal*mart for $6 in the craft section. Pretty much you can add just about anything you want.
For a more dreaded look, try yarn wraps or braiding yarn together.