Singing is a difficult thing to master. You may sound good or have a good voice, but if you want to get playback quality voice you really need to work hard , practice and even take professional singing lessons. Lets take a look at some common mistakes made by new singers and how you can avoid them and go to next level of singing
Common mistakes made by beginners and what should be avoided.
1. Beginners expect voice to transform overnight or in a week or month. Singing success is not an overnight activity. It takes years of practice to become a singer or a playback singer. However this should not discourage you. in case you have a good voice then you probably already sound good. All you need to do now is keep improving day by day and that will motivate you to perform better. Anyone can sing with dedication and proper training
Check the simplest way to create an impact while singing. Vibrato can be easily achieved by doing Siren exercises. Vibrato is an effect consisting of a regular, pulsating change of pitch. It is used to add expression to singing. Vibrato is typically characterised in terms of two factors: the amount of pitch variation ("extent of vibrato") and the speed with which the pitch is varied ("rate of vibrato")
This Video will show you basic way to learn Vibrato, without a piano.
Its certainly not 'dangerous', but it's not very effective. I myself had seen many books and videos and DVDs all over about teaching yourself to sing, but none of these can actually give you feedback from any of them. Sometimes your FRIENDS or your spouse can tell you that you sound great or not, but they wont be able to point out the mistakes and hence will not be able to give any deep rooted constructive feedback.