The sensor nodes deployed in wireless sensor networks (WSNs) are strictly energy constrained. Thus energy conservation for maximizing lifetime of the network is central to the design of WSNs. In many applications, the nodes nearer to the sink are overburdened by means of huge traffic load as the data from the entire region are forwarded through them to reach to the sink. As a result, their energy is shaded rapidly and the network is partitioned. This is commonly known as hot spot problem. On the other hand the equal size clusters waste energy according to the network density. This problem is called equal size clustering problem. In this paper, we address both the hot spot and equal clustering problems and present unequal size clustering and routing algorithms by considering the energy efficiency of the WSN. The algorithms are tested with various scenarios of WSN. The experimental results show that the proposed algorithms perform better than the existing ones in terms of life time of the network, average energy consumption of a node and number of active sensor nodes.