there are a lot of small near-practical applications, but it all really revolves around trying to be cognizant that our initial impressions/estimates vary wildly and are biased.
The book spends the entire time giving you countless examples to hammer the point home.
My favorite example from the book (via wikipedia)
Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.
Which is more probable?
a) Linda is a bank teller.
b) Linda is a bank teller and is active in the feminist movement.