Difficult Conversations
Nonviolent Communications
Many here on HN get PTSD with the last one, but ignore them - everyone I've engaged in on HN that criticizes the book hasn't read it (the book actually agrees with their talking points!) However, I will say that there is a cult-like following the book has (NVC chapters in various cities, etc), and would recommend you read the book and avoid the cult. The latter often adds stuff that is not in the book.
From my experience, merely reading wasn't enough. I took notes from the books, and compared the content across all three before it all really started clicking.
And expect it to take years to change your communication style. Don't give up, though. I'm nowhere near where I want to be but I am better. Even though it's hard for me to change, it is easy to recognize when others are practicing it, and I can witness first hand how well it works. Most of these people have not read the books, which in a sense speaks to the universality of the approach.