As Romeesa pointed out, the club itself matters. Every club may have their own kind of demands from the people they appoint, especially for a higher post, so you must be proficient in that area.
Other than that, the first impression is the last one. Dress modestly, and if there is a uniform then follow it and make sure you have groomed yourself--polished shoes, combed hair, brushed teeth and hopefully no bags under your eyes. Sit confidently, no need to sit stiffly like a medieval slave or lounge as if its your drawing room.
The way you talk also is very important, not just your command on language. You should be audible, mumbling or talking very loud are both unacceptable. Don't just give one-word or one-liner responses, relying on the interviewer to question you. Your answers should be thoughtful and extend beyond a simple answer, so that you can show your confidence in conversation and depth. Don't ramble, though; the more useless conversation you make, the more likely you are to say something wayward and you don't want to make the interviewer feel ignored. Depending on how your interviewer is, cracking a few harmless jokes is a good idea, as it shows you're not a dull person. Though, if your interviewer seems rather sober, you can also quote points from current affairs or famous authors, as that should impress him.
Be polite, following general etiquette and remember to seem charming about it, not frightened. No one likes wimps.
Build your confidence and prepare yourself by rehearsing important, base questions in front of the mirror. Hand gestures are good, as they are a vital part of communication, as long as they do not see intrusive or ridiculous when talking to someone.
Best wishes for your interview! Remember to trust yourself and give it your best.
