Wireless Sensor Networks (WSNs) are being used extensively for monitoring and surveillance in several fields like military area, agricultural fields, forests, nuclear reactors etc. A Wireless Sensor Network generally consists of a large number of small and low cost sensor nodes powered by small non rechargeable batteries and equipped with various sensing devices. It is expected that it will be suddenly active to gather the required data for some times when something is detected, and then remaining largely inactive for long periods of time. So, efficient power saving schemes and corresponding algorithms must be developed and designed in order to provide reasonable energy consumption and to improve the network lifetime for WSNs. The cluster-based technique is one of the good approaches to reduce energy consumption in wireless sensor networks. The lifetime of wireless sensor networks is extended by using the uniform cluster location and balancing the network loading among the clusters. In this research work various energy efficient schemes apply in WSNs have been studied. The clustering based approach has been studied and a modified protocol has been implemented which is based on selection probability. The sensor only transmits when the threshold level is achieved for this selection potential. It selects a node as a cluster head if its residual energy is more than system average energy and have less energy consumption rate in previous round. The goals of this scheme are, increase stability period of network, and minimize loss of sensed data.