Try something different for a shoulder-grazing bob by giving it edgy piecey waves at the ends a la Ashley Olsen. This style is supposed to have a casual feel, so don't worry about getting the waves perfect.

Get her look: Add a texturizer to towel-dried hair. Gather hair back into a ponytail, twist, and secure with an elastic. Remove elastic when hair is dry, and gently run fingers through hair to separate waves.