I want to read some great books on how to talk to people, how to handle people's unfriendly comment non-defensively, how to turn a potential quarrel to a friendly and pleasant talk. I know there is a great book in this field called "How to Win Friends and Influence People " by Dale Carnegie. Do you know any other good book about this?
Getting to Yes by Fisher/Ury/Patton. It's about the "Harvard principle" in negotiation. Very useful as a general book about communication, I think.
Basically: Try to see the issue from their side. Walk in their shoes. All decisions everybody makes are logical, from their standpoint, with the info they have, and with their interests in mind. Nobody ever makes illogical decisions. So argue their points, not yours. And help them understand where you're coming from.
Apart from the Dale Carnegie books, which are a de facto standard, most books offer things that, if you didn't learn them by now, you are in trouble as an entrepreneur. To that effect, if you need foundational help, a book like "How to Talk to Anyone" is good for the basics. (Be careful, though, as the book has a poseur-ish, stratified flavor.)
Then, you can likely benefit from intro psych books for counseling.
The main idea to always keep in mind, before getting confused by multiple book techniques :), is: "Approach conflicts as opportunities."
In all honesty a fun and very quick read is a book titled "Who Moved My Cheese." While it does not necessarily give you real life examples on how to talk to people, it is a metaphor for life that will allow you to really put things into perspective.
Also look all around you. There are lots of good examples of people doing this in real life. Emulate them...