Instructions
Start "The Sims 3" on your computer.
Select the Sim who needs a haircut to from the icons of your Sims on the left side of the screen.
Click on any mirror in the game to bring up a list of options. Select "Change Appearance." This will bring you to the "Create a Sim" section of the game.
Click the "Hair" option on the left.
Select one of the two main styles available: "Hair" or "Hair with Accessories." The latter has options that include styles with hairbands and hats.
Select the hair style you prefer from the list. There are quite a few, so you may want to look at more than one.
Change the color of your Sim's hair if you want. The default color options are laid out below the hair styles, but if you don't find one there you like, you can click the "Change Color" button below them to create your own look.
Click the "Accept" button when you're done. This is the button near the bottom of the screen with a large check mark in it.