In wireless sensor networks (WSN) trust plays a very important role, which is one of the most popular network technologies for the Internet of Things (IoT). The efficiency of the trust evaluation process is largely comprised by the trust derivation, as it influences the overhead in the process, and performance of WSNs is particularly sensitive to overhead due to the limited bandwidth and power. This paper extends the previous work of energy aware trust derivation scheme using game theoretic approach, by increasing the overall trust derivation process and improving the energy consumption which manages overhead while maintaining adequate security of WSNs. A risk strategy model is first demonstrated to stimulate WSN nodes’ cooperation. Then, a game theoretic approach to secure report reading and trust derivation algorithm is applied to improve the overhead of the process. We show with the help of simulations that our improvement in the overall trust derivation scheme can achieve both intended security and high efficiency suitable for WSN-based IOT networks.