Step 1: Dress for success
Anticipate what the rest of the crowd will look like and use common sense. Avoid bright colors or revealing clothing. Avoid anything that could get people to pay attention to you. Avoid being too out of style and too in style. Avoid things with big logos or graphics on it.
In most situations the ideal outfit has dark muted colors, is clean, covers your naughty bits and matches. It should have a timeless look.