I would start with two materials:
- Influence, by Robert Cialdini, which explains in detail how salesmen and other compliance practitioners use psychological techniques to take advantage of us.
- The last chapter of Poor Charlie’s Almanack, called The Psychology of Human Misjudgment, which is a talk given by Charlie Munger (later rewritten as an essay). It explains a lot of various biases the human brain is subject to. Very impressively Munger figured that out a long time before Kahneman published his work on rationality in Thinking, Fast and Slow. Fortunately, you don’t have to buy the book to find the text. It is also available (with permission from Munger) on the Farnam Street’s blog. If you like it, buy the rest of the book, it is great.
Behave by Sapolsky is also a very good book, although it looks at behavior more from a biological point of view (genes, hormones, environment) than a psychological one. I learned a lot in this book, but it is not very actionable, whereas Influence and The Psychology of Human Misjudgment are more useful in everyday life.