There are several heated scenes in Breaking Bad where Walter literally buys his life out by convincing his enemies using precise words. But why is he so good at it, he clearly does not have 20 years of hostage negotiating experience yet he is effective every time? Is it him just being a genius by nature or maybe the fact that he has to speak in front of a class everyday? This aspect of his character is fascinating in my opinion.
Walter White HAS negotiation experience but not street wisdom. Walter White was the co-founder of Gray Matter Technologies and helped in a research regarding photon radiography; he contributed to a project that was awarded the Nobel Prize in Chemistry, awarded jointly to Herbert A. Hauptman and Jerome Karle for outstanding achievements in the development of direct methods for the determination of crystal structures. Also, there's an interesting paper made by Jennifer Reynolds where the Walter's techniques are analyzed. Jennifer wrote about this:
His ability to use conventional negotiation techniques in unconventional ways reminds us that negotiation techniques do not come with ethical guidelines for use. Indeed, when we ourselves negotiate, it is easy to start thinking about the people on the other side instrumentally—as pawns that need to be moved into position, or as obstacles that need to be eliminated, or as resources that need to be utilized. This creates an inevitable ethical tension.
Short conclusion: he had enough experience to success every negotiation, legal or illegal.