General Rules

Speak more slowly when on camera.   About 10% slower is best.  Keep voice at its natural volume.  Do not pause at the beginning of an answer.  If you must pause, do it at the middle of the answer.

From the moment you are in the room with a camera, act as though it is on and on you.  Always act as if you are on camera, even when listening to a question.

Do not react to outside stimuli when you are in a TV studio.  Always act as if you are on camera.

If someone is talking and you are going to disagree with him, an understated little smile and a shake of the head will work wonders if it gets on camera.  Do not overdo this thought.

Dress

Men - Always a suit and tie.  No white or black.  A light gray shirt is the best.   No bright red, but a burgundy or maroon tie is okay.  Long socks.  A translucent pressed powder will keep you from shining.  Make sure it is of a medium hue and oil control.

Women - On color solids that go from top to bottom.  A clearly defined pattern is okay.  Wooly or nappy sweater is great.  If she is wearing a jacket or sweater, the dominant color should be on the inside.  Small and tight jewelry is okay.  There should be one inch between the eyebrows and the hairline.  Street makeup is fine as long as you end with powder.