Cecilia Nam is a really great voice teacher and singer. Here’s her speech at the 2013 CMAA Colloquium, which should be helpful to singers in any style.
Basically, if you’re singing correctly and if you’ve practiced and learned the music, you shouldn’t have to kill yourself trying to breathe and hit notes and so forth. It should all come along in an “effortless” package. If you’re working too hard to do normal things, you might be doing something unhealthy; or you might not be getting the prior preparation and practice done.
So there’s a lot of talk about how things work, and some great freaky vocal exercises for your entertainment and improvement. There’s also a lot of mythbusting of bad voice advice.