The last bullet (arguably the last two bullets) are about conversation skills, but that is an essential part of negotiations.
I won't claim to be good at this stuff. It takes a lot of effort and practice to change habits you've formed your whole life. But still, I've improved somewhat. What I do think I've become much better at is identifying why someone's efforts succeeded (or in this case, failed).
I would also recommend Influence by Cialdini. It is not a negotiation book at all, but will make much of the material in those books more meaningful if you've read this book.
Books/courses I discourage:
- Never Split The Difference
- The Lynda course (there may be more than one now, but the one I took years ago was bad).
