Discipline is one way of helping your child learn about your values, how to get along with others, how to keep safe and how to develop the necessary self-control to do these on his own. Discipline means teaching - not punishing. It's about setting limits and communicating values. And it's about creating rules that make sense and really matter.
In all discipline, it's important that you make it clear that you are the one in control. Remember that it's not helpful to be harsh, but it is necessary to be firm. It can be frustrating having to tell your child something over and over again, but it's important that you set a good example in handling your own anger and frustration. The example you set will play a big role in helping your child learn to manage her own behaviour.