DS12's favorite words when he was DS2 were:
Me Do!
Me Do!
Me Do!
I found that if I slowed down and thought before I said 'no' then very often I could avoid lots of arguments.
As far as being the boss with others, I think it's ok to say:
We use kind words, if we don't use kind words then we go home
...and do.
As I remember my kid was throwing rocks at others at age 2, so perhaps being verbally pushy isn't such a bad thing.
Also, try not to feel like a faliure if she has a tantrum when she doesn't get her way. It's a release of frustration, no more no less, until people around her start caving in and changing their behavior.
I love the above suggestions, and will reccomend the books here:
http://www.researchpress.com/product/item/4628/'I can problem solve.' I read it too late to be of much use, I'm thinking that for gifted kids, age 2 or 3 might be just perfect. Please let me know, as I've been itching with curiosity ever since.
Best Wishes,
Grinity