D.D.
There is an excellent book called Easy to Love, Difficult to Discipline. Barnes & Noble has it. Best book/class we ever invested in. When she hits, sit down at her level right then. Take her hand and have her touch you softly on the arm. Say "we touch soft." If you tell her to stop hitting, she will only hear the word hitting. We used this method and it worked like a charm. The book is fabulous.