I always do regular vocal exercises and would reccomend any singer to be doing so. The voice after all is a muscle and like any muscle needs exercise to stay healthy and strong. there are lots of exercises on line now, just pick one that suits you. Runing through the scales i.e do rae me fa so la ti do and breathing exercises will make anyone a better singer, and will give you better volume, amazing how many otherwise good singers one has to struggle to hear