How to Win Friends and Influence People covers a lot of ideas. A good way to understand the book is to learn the general principles underlying the book. Then we'll cover a checklist for two common situations:
1) how to approach arguments,
2) how to give feedback and change someone else's behavior.
Principles
People crave the feeling of importance. Make someone feel important and they will think well of you. Diminish someone's importance and they will resent you.
Appeal to the other person's interests. Virtually all people care more about what they want than what you want.
You wouldn't go fishing with cheesecake as a lure, since fish don't like cheesecake. Go fishing with worms.
Keep asking yourself - "what is it that this person wants?"
etc.