A while back, I asked other members for discipline and child psychology books. Someone recommended Easy to Love, Difficult to Discipline by Becky Bailey. Of all the book recommendations I got, and other books that I picked up off of the library shelves, it seems the best.
It sheds a lot of light on the mind of a child, and how to work with her where she's at in order to meet your needs and hers. Once you see how Bailey's ideas work - she includes lots of examples - the discipline part gets so much easier.
The most important thing I've gotten out of it is that rudeness and misbehavior pinpoint where a child needs to learn the skills of how to appropriately get her wants and needs met (and sometimes there is an underlying need to a want that can be addressed, even if the want can't be fulfilled at the time. Bailey helps parents see what those needs are, like independence, security, a feeling of importance, etc.). Bailey points out that just saying "No, don't do that," and punishing children doesn't work in the long run because children are strangers in this land, so to speak. They must be taught the specifics of how to behave, not just what not to do.
It's also important, she says, to see the good in your child and to understand that her actions don't express disrespect but confusion and upset, which are very different things. Tantrums, too, are not a means to manipulate and be disrespectful. They're not a form of misbehavior, they're what happens when tough emotions become too much for a child to handle. Tantrums are very frightening and painful for children, and, like all acting out, will need empathy from the parent to calm the child and get her to listen. Just forcing a child to suppress such strong feelings is unhealthy for her because she learns to cut herself off from her feelings, which, if provided guidance, help her to internalize right from wrong and to discipline herself as the years go by.
Also: focus on what you want, not on what you don't want, because whatever you focus on, you get more of.
Really, get the book and the detailed descriptions will be so much more helpful than I can be here with a summary. I think you'll find it to be a big relief.
Good luck!
L.