Reddit mentions of Influence: How to Make the System Work for You - a Handbook for the Modern Machiavelli

First example is what the author says about do's and don'ts in the (TV) studio (which could just as easily apply to a job interview).

>- Choose a stable, upright chair.
>- Lean forward a little, square on to the camera if possible. Never slouch no matter how comfortable the chair.
>- Always look at the interviewer or whoever is talking; do not look at the camera.
>- Do not allow your eyes to wander to the left or the right or you will appear shifty.

This is something said about answering questions in public.

> Take the heat out of an antagonistic question by appearing to agree. If your company has investments in South Africa, for instance, you can say, 'You are absolutely right to ask this question. We all abhor apartheid. But the way forward is to ...'.

Specifically on electioneering.

>I am constantly amazed at how things like dress, hairstyle, perceived attention span (looking over the shoulder of the person to whom you are meant to be talking to spot more important people in the room is a sure vote loser - we can all admit to do doing this sometimes) and other presentational matters which can be rectified seldom are. As in so many areas, such little niceties win out over policies again and again.

Edit: - Source UK, or US version.