In Cognitive Radio Networks secondary users are aware of their surroundings and can use free primary spectrum opportunistically. Higher spectrum sensing efficiency is needed to implement Cognitive Radio Networks. Thus cluster based topology is used to increase sensing efficiency. The secondary users are divided into groups or clusters which have a cluster head and the decision of the spectrum sensing taken by all the secondary users is controlled by these cluster heads in their respective region. This paper proposes a new optimized cluster head rotation and selection scheme. Practical environmental scenarios for mobile communication like fading and shadowing are taken into consideration. The comparative analysis with previous known techniques confirms that the proposed approach performs better for cooperative cognitive radio networks.