You can't anticipate everything in a job interview, but there are two things you can do to prepare: your presentation and your knowledge about the company before going into the interview.
There are many aspects of a job interview that you can't control by mere preparation. Sometimes, no matter how prepared you are, you'll still have an attack of the nerves or be totally thrown off guard by a random question. But there are a couple of aspects you can be in complete control of going in to an interview. They are: your presentation and knowledge of the company.
I was going to say "neatness counts" but that's so cliché that I would feel like slapping myself for actually having to say it. (But it's true.) You don't have to be dressed to the nines, but take care in how you look. (You know, no flip flops or tuxedo tee shirts.) Who would want to trust a job to someone who couldn't even keep his personal appearance together?
Give the interviewer your undivided attention. Again, this is something I shouldn't have to say except that I heard the other day about a job candidate actually reading a text message during an interview. Unless you're expecting an organ donation, turn off all the electronics before stepping into the building.
Knowledge of the company
With your IT skills, you could probably get the CEO's blood type in a few minutes, so there's no excuse for not going online and researching the company. You will probably be asked what you know about the company. Saying "I didn't have time to research it" is not an acceptable answer. It's not like they called you six minutes before they wanted you in for the interview.
If an interviewer asks what you can do for the company, it's tempting to show your eagerness and say you can do anything they want. In reality, however, that speaks more of desperation than eagerness. Keep in mind that no one knows you as well as you know yourself. In your mind, you might be able to adapt anywhere, anytime. But the interviewer has neither the time nor the inclination to translate your answers to see where you would fit in the company. It's up to you to market yourself.
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