Significant advances in wireless and integrated circuits technologies have made the manufacturing of the Wireless Sensor Networks (WSNs) possible. WSNs have military, health, commercial and industrial applications. Even though this technology seems promising, to make it fully practical, considering many factors during the design of a WSN is essential. WSNs have attracted attentions of many researchers in a wide range of topics as Energy Consumption Optimization, Localization Error Minimization, Robustness and Fault-Tolerance, Self-Configuration, Area Coverage, Routing, and Security. As our contribution, in this research book, after reviewing the history and applications of WSNs, we will concentrate on optimizing energy consumption and minimizing sensor nodes localization errors. In order to optimize energy consumption, we will propose solutions based on multi-hop communication and dynamic clustering. For minimizing the localization errors of sensor nodes, we will introduce a method based on regular distribution of anchor nodes and getting weighted average among distances of a sensor node from its surrounding anchor nodes.