At a job interview, you have roughly 15 minutes to sell yourself as the perfect person for the position. It’s likely all other applicants are better than you in qualifications, presentation and anything else that you might think counts. But there's a catch here. All of these can be compensated for, if only you have the right approach about it.

As far as your qualifications go, you wouldn't be applying for the job, if you didn't fit the criteria. If you do, you're obviously not too bright and you're going to die alone.
On interviewing some of the senior directors at the company that I was lucky to avail an internship at, I've come across some interesting quirks that easily backfire and cost you a sure thing.
For example, did you know that your appearance isn't really of much importance in the Bangladesh service industry? Don't get me wrong and don't you dare show up in t shirt and shorts, but if picking the right tie is making you late for your interview, you might as well stay home. Because we're in Bangladesh and most of your employers won't care if you wore stripes with stripes.
For those of you, loading up your cv with one job after the other to make it look impressive, stop! Find a job and stick to it. Your employers want stability and they're going to look for your future prospective in their company. Telling them you plan to go abroad and make it big, won't impress them.
As for the cold, strictly business demeanor that is advised in almost every corporate guide book (Or as most of you gather from movies and tv shows), I'm going to remind you again, that this is Bangladesh and we're only at the beginning of pseudo-division of labor. Your employers are going to look for someone whose a team player, and easy to work with. So yeah, against all advices, be warm.

The last piece of advice I have to give you is to know your place in the food chain. You need to do enough research and know what you can ask for. Asking for too much will backfire just as much as asking for too little. Barring all these reasons, there's always a chance of your interviewer just hating your face so much. In which case, you're on your own, toots!