Pitch correction is used mostly as a post production tool.
The best way to learn to sing better is to sing! Learn to play the melody and sing along with that. Learn different styles, emulate different artists soon you will develope your own style.
So many things make a good vocal, even if you sing on pitch if you don't have a pleasing voice people still won't like it.
We have all heard singers that technically sing right on pitch yet there is still something about their voice that doesn't sound right.