The biggest selling mistake a salesperson can make (and there are dozens of worthy considerations) is not understanding the critical importance of customizing their presentation style to fit their prospect’s temperament style. In short, when it comes to people, one size does not fit all. Each of the four temperament styles (Aggressive, Expressive, Passive and Analytical) requires a slightly different marketing and presentation approach. The bottom line in the selling process is building trust and rapport, not lowest price or highest quality. Sales reps who have not yet learned how to identify their prospect’s temperament style leave tons of business on the table for those reps who do.