I am reading date to discipline and highly recommend it. I plan to read the string willed child next. Dd is 21 mos and I know I am going to need both:/
Apparently it's the age...we have the same issue with dd and she's 4. We've found that telling her if she does x then y will get taken away (tv, her favorite stuffed dog, leapster, etc). Or, if she does x, then she won't get y (ice cream, popcorn, snack, etc). The key is to follow through with it.