P A N

i can't truthfully say that improper technique is damaging to your vocal chords because some people use the callouses developed via screaming to more consistently achieve their sound... which indeed could be looked at synonymously with smashing cracked and broken cymbals rather than glancing a nice, intact and well-taken-care-of cymbal.

but there are numerous exercises you can do to help loosen your musculature to facilitate comfortable vibrations. i recommend picking up a book with diagrams or finding diagrams on the net somewhere.

referring to my first point though, it's all about your sound. if you wanna sound like an opera singer, you're going to need a opera-singer regimen to follow. if you wanna sing like janis joplin or tom waits, you have to have an individual outlook on the world and lots of cigarettes to smoke.

you can also get a tuner of some kind (i use a software version that is always on my desktop) to make sure you're hitting the right pitch. something to record your voice maybe 2 or three times a month singing the same thing can help you develop consistent tone too.

really though, you're a human, and like animals, we humans come equipped with a very articulate nervous system which will tell us when we do and when we don't like the way something feels or sounds... people will like your sound if you are in tune with that... because that way it is your voice and not an attempt at someone else's voice which comes from your body. singing happened long before schools of music. it's just a natural thing we do, and i thusly believe that there is no way to indoctrinate or gentrify or standardize the ways by which we do it.

...but we do try, and that's why we have mainstream music and a lot of autotune usage.