As an enterprising art scientist, I plunged into the world of sales in 2017. In two years time I doubled the turnover of two roofing companies. In total, as a seller, I have sold more than 4 million euros worth of projects in the past 5 years. I have converted more than 1000 sales calls into a successful deal. As a complete layman in the construction industry, how could I convince so many customers in a short period of time? I asked myself that and started reading about sales and sales methods.