It takes practice. I am good at expressing exactly how I feel in ways that don't offend other people, but it has taken years of practicing how to do it (through trial and error) to get it right. I have six younger siblings and I have been part of a military community that for the most part doesn't agree with my point of view on a lot of things, so learning how to do it so that I can be honest about myself and still keep my relationships in tact was essential for me to be happy. I think it all comes down to remembering that your feelings and opinions matter as much as the next guys, not being afraid to express them, and always keeping how what you say may sound to other people in mind. There is little point in expressing what you think or how you feel if you don't do it in a way that the people you want to hear it can receive it without getting defensive. You have to be willing to explain yourself again without becoming defensive yourself if what you said didn't come across in a way the other person could take it without feeling attacked.
I have no idea if that is what you were talking about, but that's what came to mind for me.
