Arrive on time: If you show up late for the interview, it’s a deal breaker AFAIAC. There are very few cases (genuine emergencies) where this can be overlooked. However, if you can’t plan to arrive on time on the first day, it reflects poorly on your planning skills.
Be well-dressed and properly groomed: Dress for the job. But don’t overkill either.
Have all your documents ready: Any working professional should have a decent idea of all required documents. Have them in one of those multi-pocket folders so that they can be easily tagged and retrieved. Having essential stuff like your score sheets, letters of recommendation, proof of previous work experience, a few copies of your resume is a basic hygiene factor.
Know the company and the job you are applying to: Go through the company website. Be thorough with their history, their strategy, current market positions, latest news coverage etc.
During introductions, get the names of the panelists. Use them in conversation. Helps create a more personal touch.
Listen, think, and then respond: Do not interrupt the panelists ever. Allow them ample time to finish their questions. Do not be in a hurry to answer, but think your responses through. If required, feel free to solicit additional information you believe would be essential for you to formulate a well-rounded response.
Come across as honest, sincere, and affable: Arrogance is one of the biggest turn-offs about people for me. And there is a thin line between arrogance and confidence. People who have a smug smile on their pace, a condescending touch to their voice, or an attitude that clearly reflects a highly inflated sense of self-worth, never make a good team player. And in any organization, teams are always more important than individuals.
Be ready with a few questions for the panel for when they ask “do you have any question for us”.
(extension to #8) Do not be scared to ask questions. The interview is a 2-way street and you have every right to know if the company is suitable for you. But at the same time, never interrupt others. Ask questions when you have the window, or when a relevant context is being discussed.
Body language: Your posture speaks a lot about your personality. Sit straight. Make eye contact. Have a firm handshake. Smiling helps.
Switch off your phone. Seriously. The world can do just fine without you for an hour. Unless there is something critical (like a sick family member, or a little son/daughter in a school that needs to be picked up), it’s better to switch off the phone. Even switching to silent mode is not enough as the vibrations in modern smartphones are pretty loud.
Don’t be pretentious. It is fine to say, “I don’t know”. Do not try to have the best story/answer for every question.
Do not compromise on your principles. Even if they offer you the job, or increased compensation to agree to immoral ways on the job later, do not do it. It is most likely another test (cue: 3 Idiots). And even if it is not, it is not worth working for a company that has a flawed and compromised moral compass.
No vulgar jokes, “-ist” remarks.
Nothing says jerk more than someone entrenched deeply in stereotypes and having preset, often unchangeable opinions about people and things, based on no real knowledge or experience.