I agree 100% with Bob. I would add that you must try not to lose out on all the more subtle vocal techniques for power though. Much as I loved him Johnny Collins used to do that a bit for me, but he had a fabulous range, and I always forgave him. Roy Harris can really project his voice. One very important thing is breath control. Listen to Harry Cox or Pop Maynard, then try singing along with them I'll bet you are amazed at Pop Maynard's control. He was in his eighties when recorded I am 63 and he beats me hands down for the control he uses. I usually run out of breath singing along with him. Above all relax and just like Roy and Johnny and whoever your favourite singer is, please have fun, that's the most important thing of all.
Here endeth the lesson....