Have you ever had the misfortune of sitting next to someone who obviously hasn't taken a shower in several days? Make sure you not only clean yourself but wear clothes that have been through the wash cycle at least once since you last wore them.
The same applies to your breath. There is always someone who wants to talk to you and when you are sitting next to them, you broadcast more than your voice when you open your mouth. Put a toothbrush to your teeth before you leave the house and buy a bottle of mouthwash the next time you visit the grocery store for everyone else's sake.
Example: Every morning there is a gentleman (a generous term) who boards the bus two stops down from where I get on. With my eyes closed, I can tell you how close he is. When he sits right next to me I have to turn my head away and breath through my shirt to keep from smelling the horribly strong cigaratte smell he brings with him.