"Talk At A Normal Tone
Many cellphone users think that it is some how better to shout into a cellphone. Apparently they perceive higher voice levels with a better cellphone signal strength. Rather than shouting, when you can't hear the other person, why not go outside or in a area with a better signal strength?
Choose The Vibrate Mode Over Ringer
I can not see any situation, apart from broadcasting your latest downloaded ringtone, that would compel you to choose the ringer over the vibration mode. The vibration mode does the same thing that the ringer was originally intended for, it alerts you when you have an incoming call, however unlike the ringer this mode is less annoying.
Remove The Earpiece
Another annoyance is the number of cellphone users who insist on talking with you while having their ear piece on. You are consistently being placed on hold in mid conservation only to hear the ramblings of another semi-private conversation. If you have to take the call, at the very least notify the other party, that way there is no awkwardness. There is nothing worse than trying not to make eye contact with someone across from you who is not talking to you."