Welcome!
Angel made some great suggestions. Charting behavior is job #1. Many of us here do not believe that ODD is a true diagnosis. If it were, there would be some sort of treatment protocol for it. There is none because so many things can be causing that behavior that manifests as ODD. Start treating those things, and ODD may start to fade.
Can you tell us more about her? Is she your bio daughter? Any mental illness or behavior disorders on the family tree? (diagnosed or suspected) If adopted any info from biomom? Drinking or drugs during pregnancy?
What kinds of things does your daughter continue to do when told not to? Sometimes the best solutions to our children's opposition is the most obvious. Despite it being obvious, as the parent, we just don't see it. It's not a flaw in intelligence or parenting, jut a flaw in human nature.
Ex. Friend was complaining that EVERY TIME they wen out to eat, they had to leave early because her son would disrupt the meal. He was constantly getting up and checking out the other tables, "spinning" in his seat, being loud and restless. this is something they did all the time, so you think the kid would get with the program, right? Well, first, the kid was 3. Second, the kid already had a diagnosis of Asperger's and ADHD. Third, they NEVER brought him any portable entertainment. ??????? Yeah, this friend expected her 3y/o autistic child to behave like an 80 y/o in this wonderfully stimulating land where all the women were dressed alike, and there were so many tables and chairs, and it was so fascinating that every table had the same stuff on it, well, he thought it was all the same stuff, but no one let him get up and check it out to verify, so it was really bugging him that he couldn't be sure if all the tables were the same, and he got to sit on this bouncy bench by a big window that overlooked the road and he could see all the cars and trucks go by but only when he got up on his knees and turned around, but he wasn't allowed to do that and then they just had to sit and wait for the food and all they could do was talk and that's so BORING. So TANTRUM before the food ever arrives.
To me, the observer, it was obvious. Let the kid check out the tables before sitting down, let him look out the window, and bring his ds, or dvd player or whatever other toy kept him quiet and interested for a while. "But then he won't learn the proper way to behave" Sweetie, then be prepared to leave due to his tantrum before the food comes EVERY TIME.
So anyway, please share nitty gritty details. maybe someone will have a solution, if only for one particular situation, that'll put you ahead of where you are now. Might also help indicate a pattern of what kinds of things set your daughter off.