I am wondering if something could be helping my singing voice.?

Question:

I am wondering if something could be helping my singing voice.?

When i sing, when there are higher notes than i can reach, i press down on my throat, around the part where my throat indents. The pressure there seems to allow me to hit these notes. Would anyone understand why that would be so? I am also a smoker, if that would help make sense of things.

Best Answer - Chosen by Asker: First and foremost pressing down on your throat is not a proper way of singing.
Second of all if you are trying to hit the upper part of your register, you first have to develop your breath support to allow you to sustain the pitch(es) you want to hit in the upper registers. Thirdly, practice yawning so that you may open up the back of your mouth. Now that feeling you get is how you should be using your head voice. When you Hit the upper head voice you should feel your nasal cavities resonate to the pitch.

Below is my professor's book which contain valuable information about the beginning studies of singing.

ps. i would recommend not smoking.