Performing in public can be both exciting and frightening for any new performer whether they are a singer, an instrumentalist, an actor or simply someone giving a speech on a social occasion. Many people who are shy at first develop into dynamic performers who can both entertain and captivate an audience.
Like any other skill, performing in public takes time to develop and there is much to be learned from watching other performers. To begin with, the best approach can be to simply take a deep breath, walk on, smile, look the audience in the eye and begin with a song you are very familiar with.
If you are nervous, concentrate on the sound you and your accompanist(s) are making and move your body to the music in any way that feels good. If you are able to enjoy yourself, this will communicate itself to the audience. Nervousness can be turned into excitement and positive energy and can actually make your natural reactions and responses to the music quicker.