Is there anyway I can learn how to sing online without teachers teaching you online?
The important to remember is that everyone knows how to sing, but if you want to sing well the best thing to do is take voice lessons. If not, then I would recommend getting a book of vocal warm-ups and then a book with the songs you want to sing and then either play the notes on a piano and then sing them(not very much piano skill required) or get a CD and sing to it. There are many CDs with vocal warm-ups you can get.
