There are other issues to consider. You should give your interviewer a firm handshake — but not so tight as to make it seem that you are trying to crush their hand in yours. You should smile in a friendly way — but not so much as to communicate an inappropriate air of jollity.
Other forms of body language are important too. Try, for example, to avoid wrapping your arms around your body. If you do so, you will appear nervous, timed or guarded — or all three simultaneously.
CLARITY IS THE KEY
Giving a great performance in an interview is often about finding the right balance. Some people are reluctant to talk about themselves at any length, and so end up selling themselves short. On the other hand, don’t chatter for the sake of it.
In your answer to every question, you should be thinking of how to emphasize your suitability for the job. Make your answers full but clear. That way, the message you are trying to communicate is much more likely to stay in the interviewer’s mind long after you have left the room.