Cutting your own hair in your home saves the time and money it takes to visit a hair salon. It also ensures that you receive the hairstyle you desire, as your hairstyle ideas are not up to a hairdresser's interpretation. When cutting your hair from a messy bob to a shorter style, it is always best to use a large three-way mirror to see your full head of hair rather than a flat mirror that displays only the front.

Wash and comb your hair. Wet hair clumps together and is easier to cut than dry hair, which may frizz, separate and spread. Comb your hair to be sure every piece is as straight as possible. Hair that is knotted or curled together will be uneven when it dries and relaxes. The hair on a messy bob will be uneven, which makes combing essential to make sure every hair gets attention.

Comb an inch of hair separate from the rest of your hair, and grab it with your forefinger and thumb. Place the strand between your forefinger and middle finger, causing a flat one-inch section of hair. Cut your hair straight across, approximately an inch and a half longer than your desired length. For bobbed hair, this procedure is best done in front of a three-way mirror so you can see the hair on the back of your head as well as the front.

Section the hair by one inch all the way around your head, lifting and cutting until your entire bob is trimmed. Use the three-way mirror to make sure your hair is even in the back of your head.

Trim hair that is too long or uneven. The inch and a half of hair left on the end allows for mistake correction and hair shrinkage as it dries. Depend on the three-way mirror to see the hair on the back of your head, and use your forefinger and middle finger to keep the cut even.

Pull your hair apart in layers, and clip the top layer to the top of your head if you prefer layers. Cut the layer closest to your head longer than the topmost layers. Use the same finger-and-scissors method to trim layers into the hair, working one layer at a time.