Sensor nodes depend on power source, but they deplete rapidly. The major issues of Wireless Sensor Network (WSN) are its energy source constraints. We are able to solve this issue by using clustering architecture. In this paper we study about various clustering techniques used in WSN. The large-scale deployment of WSNs and the need for data aggregation resolve this issue mainly. Clustering is best approach. We present the design challenges and objectives of the different clustering approaches. Clustering is the grouping of sensors. In clusters, sensors send data only to Cluster Heads (CHs) and then the CHs send the aggregated data to the processing center or Base Station (BS).