A very small gesture with big results is eye contact. Making a direct connection with people in the audience pulls them in and engages them. They feel as though, even if only for a fraction of a second, you are signing directly to them. Looking away from the audience for too long causes a disconnect. The crowd may not feel as though you are invested in putting on a good show for them and could react by pulling away. Any show suffers when the audience lacks interest.
Walk around the stage before the show. Learn the size and dimensions, where to look into the crowd and the best positions to peer into different areas of the audience. Similarly, walk around the rest of the performance space, into where the audience stands. Check out the view of the stage from different angles. Locate where to stand so the most people can view the performance. Determine how the sound plays through the room. See how the lights effect those standing or moving across the stage. No performance can happen without an audience, so knowing what they see and hear during the show goes a long way toward making it a better experience.
Even if you're a singer who is more concerned with notes and slurs than in clear lyrics it's important the audience is able to understand what you're singing in order for them to connect to the performance. As with any personal exchange, being understood is important to communicating with an audience. A disengaged or unemotional performer makes the audience less interested in revealing their own emotion. A performer can't just sing the song, they need to feel it. Show the emotion of the song in your face, such as smiling during a happy song or looking angry during a more aggressive one. Remember that performance is a conversation with the audience so make them believe you're feeling what the song feels. Deliver the song with the right degree of happiness, resentment, melancholy, anger, joy or whatever other emotion the song includes, while always keeping the lyrics clear and distinct.
A singer's movement and mood should reflect the energy of the song. Dance during dance songs, run around and yell during loud songs and sit down during slow songs. The manner of the singer should mimic what is being sung. Limited, slow movements or sitting down create the intimate and somber feeling necessary for ballads. Happy, upbeat songs need loose, open and welcoming gestures. Intense, hard-edge songs require a strong, aggressive presence.
Confidence can make singers with a weak and limited voice into a commanding, remarkable performer. Even if you are uncertain about the performance of a song, or have sung it to the point of boredom, any disconnection from the song can cause the audience to pull away. Perform the song as if it the greatest thing ever written, and your voice is the only one that should ever sing it.