Consistency is key- there must be a consequence EVERY time she is disobedient. Also, remember that 2 year olds are often frustrated because they want to be independent, but lack all of the skills necessary to be independent. Although it is extremely frustrating, she is just imitating you when she points her finger and tells you no. She doesn't know her boundaries, so it's up to you to set them for her. This is a learning time for her;she's learning that there are many things that mommy/daddy can say or do that she can't, so be patient.
Don't make everything a battle. Choose your battles and allow her to make some decisions of her own when possible. This may cut down on some of her behavior problems. Also, try giving her a heads-up when she's playing and you need her to switch activities (i.e. You could say, "In 2 more minutes, you can put your baby doll down to sleep and come get ready to eat dinner." You can set a timer, since she has no real concept of time) This way you're not just abruptly stopping her play time with orders to do the next thing.
I hope this advice helps. Remember, it's only a phase and things will eventually get better! Good luck!