Multi-Hop Wireless Self-Organizing Networks (WSONs) have attracted considerable attention from the network research community; however, the key for their success is the rigorous validation of the properties of the network protocols. In particular, applications of risk or that demand precision require a rigorous and reliable validation of deployed network protocols. That is the reason why many efforts have been performed in order to validate the requirements and the functioning of protocols in such kinds of networks. It can be observed, however, that, even if different communities have carried out intensive research activities on the validation domain, WSONs still raise new issues and challenging constraints to these communities. The goal of this tutorial is to present a comprehensive review of the literature on protocol engineering techniques and to discuss difficulties imposed by the characteristics of WSONs to the protocol engineering community.