Proper utilization of wireless sensor networks (WSNs) has direct impact on various application developed using it in our daily life. In the past years wireless sensor network is popular area of research due to its applicability in different real scenario like border surveillance, fire detection, underwater application, IoT, body area network, irrigation system. The large number of nodes cooperatively performs a specific task. The nodes work in hazardous environment where human intervention is not possible. The battery power is limited, so proper clustering helps to maintain the network life significantly. There is wide variety of methods to perform clustering. This paper presents general classification of state-of-art clustering schemes.