Learn how to breathe properly as it relates to singing to increase your power. Practice breathing exercises that will increase your power such as trying to blow a feather up in the air and keep it up there with only your breath. Try to blow the feather in different directions to get real directional control of your breath.
Use your chest voice to become a more powerful singer. Place your hand on your chest while you are singing to make sure that your chest vibrates while you are projecting. Your chest voice is the most powerful technique to use to increase power. You should feel your chest swell and vibrate as you sing notes.
Combine your chest voice and your head voice. Your head voice is the type of singing you use to create a falsetto sound. In and of itself, it is not very powerful, but if you combine it with your chest voice, you can get more power. Many singers only use one or the other, but you can perform exercises that will allow you to use both at the same time, effectively increasing your overall power when you sing.
Work with a qualified instructor to find the right combination of practice routines that will increase your power. Professional vocal coaches can help you find your range, and when you are singing in your natural range, your voice is more likely to be strong and powerful. Make your vocal coach aware of your desire to sing more powerfully and ask for tips and exercises that will push you to do this.
Sing along to powerful Broadway songs. Broadway singers often use their power to be heard rather than the microphone and amplifier systems that you hear at rock and pop concerts. Pick Broadway songs that require you to sing powerfully in order to sing them properly. Look for singers who do this effectively and try your best to mimic their sound.