Sometime after reaching Level 11 in the game, you will get a call from Sandra Kirkland, your real estate agent, who asks after your hair game.
After hanging up the call, travel to the newly unlocked borough of Brooklyn in New York, and chat to Sandra on the street.
Sandra will tell you that Brooklyn is an up-and-coming neighborhood, which attracts all sorts of people, from all walks of life.
And what those people have in common, of course, is that they need regular haircuts! This is where the new hair salon comes in.
Sandra will ask your character to follow her inside so she can give you a tour. You will automatically do so and this completes the goal.