Ofcourse, as Mac said, it is very nice and importand to keep in tune. But believe it or not; that is not the hardest part of singing. Singing requires you to train and control a whole lot of muscles. Knowing wich muscles and how to control them is the real trick.
When you have a good technique you will be able to sing in tune easilly (that is, if you have a trained ear...)

You may want to look into these two world renown and proven singing techniques: EVTS and CVT

There are some excellent books out there on these techniques, but be warned: you can not learn the techniques properly without some sort of vocal coaching. A vocal coach (or singing teacher or whatever you want to call it) can see, feel and hear if you are doing things the proper way. The proper way is the way that will not hurt or damage your voice! This may vary from singer to singer. Even if you would take a few lessons you would be pointed in the right direction and you might be able to actually feel if what you're doing is what's discussed in the books.

Last edited by Mike sings; 12/13/12 04:05 PM.
Mike
www.mikewever.nl