Difficulty: Moderately Challenging
Step1
Know the difference between your head voice and your actual voice. Many people think that I can sing high but they are singing in false signing voice. This is also known as your head voice.
Go to a piano and play the scales, as you sing the scales listen to when your normal singing voice becomes your head voice.
The good thing is that your head voice is a map to how high your normal singing voice can be extended.
Step2
Singing consist of using the right muscles the right way. You should be breathing correctly in order to get the best foundation to build on. If you have not taken a few singing lessons, this may be the best time to get this done.
Learning how to sing correctly will assist you in extending your vocal range. Your posture also plays a big role in how you will sing and the quality of your voice.
Step3
Always warm up before performing. I even warm up my voice before I give a speech. This helps you stay in tune with your voice and allows you to know where your trouble spots may be.
Step4
exercise your voice daily. Scales and other vocal acrobats will give you the technique and build the muscles to help you not extend your vocal range but will cause you to have a more strengthen and a better quality of sound.
Picture taken from http://gingersnaps.files.wordpress.com/2007/05/singing.jpg