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. Applications of risk or that demand precision (like alert-based systems) require a rigorous and reliable validation of deployed network protocols. While the main goal is to ensure the reliability of the protocols, validation techniques also allow the establishment of their correctness regarding the related protocols' requirements. Nevertheless, 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. We advocate thus, the use of complementary techniques coming from different research communities, to efficiently address the validation of WSONs protocols. 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. Following the formal and non-formal classification of techniques, we provide discussion about components and similarities of existing protocol validation approaches. We also investigate how to take advantage of such similarities to obtain complementary techniques and outline new challenges.