Visit a barbershop. Talk to the barber and request him to give some pointers about barbering.
Show the proper way of using a barber's scissors and razor.
With the help of a barber - learn how to cut hair properly, demonstrate the proper technique of cutting hair, and demonstrate how to use a whetstone and a stropping belt for sharpening scissors and razor.
Cut the hair of three (3) of your friends to their satisfaction.