A professional clipper cut should never leave you with visible lines in your hair, but occasionally this is the case. These lines -- known as demarcation lines or steps among barbers -- can make your haircut look unfinished. There are several techniques for blending these lines into the rest of the hair. One approach is the "clipper-over-comb" method. It is recommended that you ask a friend to assist you in this as it is difficult to do on your own hair.
Comb the slightly longer hair above the demarcation line from underneath to bring it away from the scalp.
Angle the comb toward you slightly so that there isn't too much hair to be trimmed between the teeth.
Hold the clippers in your other hand with the guard removed and switch them on.
Run the clipper blade along the side of the comb nearest you from right to left to evenly trim the ends of the hair.
Comb the hair back down onto the scalp to check that it is even. Repeat the technique with the comb slightly more vertical if more hair needs trimming.
Repeat this process over the whole head wherever steps or demarcation marks have occured until the haircut is evenly blended throughout.
Drying the hair before blending will allow you to see how the hair will lie after being trimmed.
Always follow the manufacturer's instructions for using clippers, and exercise extreme precaution when using them without the guard.