Wireless Sensor Networks (WSNs) are crucial in a wide range of applications, including environmental monitoring and industrial automation. Nevertheless, the finite energy resources of sensor nodes present a substantial obstacle to the durability and dependability of these networks. Energy-efficient optimization techniques are essential to prolonging the network lifetime and ensuring sustainable operation. This paper comprehensively reviews state-of-the-art energy-efficient optimization techniques for enhancing network lifetime in WSNs. We categorize these techniques into several key areas, including data aggregation, routing protocols, sleep scheduling, energy harvesting, and cross-layer optimization. Through an in-depth analysis of each technique, we highlight their strengths, weaknesses, and applicability in different WSN scenarios. Furthermore, we identify emerging trends and future research directions in the field of energy-efficient optimization for WSNs. Based on our knowledge, this is the first paper which includes all the recent papers from the year 2021 to 2024. Additionally, we suggest the hybrid approach named stochastic gazelle optimization (SGOA) algorithm for network lifetime optimization.