S.G.
My daughter is 4 and I have the same problem. We have a chore chart, where she gets a sticker on the chart for 1) getting dressed without a problem 2)brushing teeth 3)making bed 4)setting table. When she gets 30 stars on the chart, she gets to either pick out something at the store (under $5) or get to go to McDonalds for lunch. This works great most of the time, as she loves to put the stickers on and loves the reward. I also make a point to praise her when she doesn't give me a hard time, and if she is, to ignore her and praise her sister who's doing it right. Mind you, we still have the tantrums, and sometimes I want to just blow up, but it does help for her to have incentive, and to make it more fun. Good luck!