Without examples of how she behaves badly, I can't give you much in the way of advice. But, having an almost 3 year old and a 17 month old I know how to handle toddlers.The biggest thing that helps me avoid tantrums is letting my kids make as many decisions as possible. I let them choose between two outfits when I get them dressed, I let them choose between two healthy snacks, juice or milk, what they want for lunch, what book they want to read, etc. Any small decision that is appropriate for them to make, they get to make. That way they feel that they have control over at least some aspects of their lives and that makes them more willing to listen to my rules.I have also always been very firm and consistent when it comes to rules and discipline. When they learned how to crawl they started learning boundaries. They always test their boundaries to see what they can get away with but they always listen to me. I don't spank and I rarely have to give time outs. I use a "two chances" rule. If they are doing something I don't want them to do I explain why I don't allow it and what will happen if they don't stop. Then they get two reminders to change their behavior. If they don't change after those two chances, they get a time out (if they're screaming, telling me "no", etc.), their toy gets taken away (if they are fighting over it, using it as a weapon, etc.), their food gets taken away (if they're throwing it on the floor or are just playing instead of eating), whatever is appropriate for the situation.They are perfectly behaved in public (even though they're often monsters at home) because they learned early on that being quiet and well behaved got them lots of positive attention and that screaming and crying didn't get them what they wanted. I have kids that are fine walking through the toy aisles of stores even if they don't get something. They know I am more likely to give in and get them a toy if they are well behaved and that whining and crying over something they want gets them absolutely nothing. I'm strict from the beginning and I've had plenty of dirty looks because I'm tougher than people think I should be on my little babies. But, as I said, I never spank, I don't yell, I just teach my kids the rules and boundaries when they're little. It makes life a whole lot easier!