Here is an example of vocal exercises which I recorded during a choir rehearsal. 
http://www.youtube.com/watch?v=zlGN7_8wcv8

Intonation, in music, is a musician's realization of pitch accuracy, or the pitch accuracy of a musical instrument. Intonation may be flat, sharp, or both, successively or simultaneously.  The vocal warm up, would help me reach the right pitch accurately. If I slowly build up the key getting higher each time this would improve my intonation. It would also allow me to work on my voice placement, as i practise warm up's changing my head voice from head to chest will become easier for me to do. Warm up exercises such as this one will also help me to improve my vocal range. The more i practise doing scales, getting higher every time, the more my vocal range will improve, which will make me more confident when I perform. Doing vocal exercises will also allow me to work on my posture. This is because I need to stand up straight, so the sound can come out freely and i won't have to force it out, if I didn't have good posture. Having good posture allows my diaphragm to expand fully so I am able to sing long notes without trouble.  I can also use vocal exercises to improve my breath control by slowly holding on notes for longer each time. This allows me to know when i need to take a breath but also allows me to learn how to support myself when singing a long note.