The unique use of layering can create height and add dimension to just about any style.  This medium length style, shown below, that Sarah Harding is wearing is a very unique type of cut.

There is layering on the sides and crown area.  The ends are left somewhat choppy.  There is a lot of height to the layers.

 

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Create this style on your own by first getting a layered hair cut.  The layers are long and start just past the ear level.  Then, add some styling cream throughout the hair and blow dry the hair using a large round brush.  Direct all layers down and under. 

To create an extra smooth finish, you may want to run a flat iron over all the layers, from the roots to the ends.  Finally, to create the height in in the crown area and sides, simply back-comb sections of hair and smooth over the top with your fingers.