The trading activities of materials retail concern an extremely competitive market. However, business people are not informed about how to proceed and what to do during marketing activities. Data mining methods could be interesting to generate substantial profits for decision makers and to optimize the choice of different marketing activities. In this paper, we propose an actionable knowledge discovery methodology for one-to-one marketing which allows to contact the right customer through the right communication channel. This methodology requires firstly to measure the tendency for customers to purchase something, and secondly to optimize the Return On Investment by selecting the most effective communication channels for attracting these customers. Our methodology has been applied to the VM Matériaux company. Thanks to the collaboration between data miners and decision makers, we present a domain-driven view of discovering knowledge satisfying real business needs to improve the efficiency and outcome of several promotional campaigns.