Looking for a job is something but actually getting THE job is an entirely different story. I have been an HR practitioner for the past 6 years and there are some things an applicant should and should NEVER do.
I have received CV's/ resumes with cover letters wrongly addressed. I understand that when one decides to go job hunting, he/she usually prepares probably more than 10 copies of their CV's so that they can float it to as many companies as they can. But please make sure that you get to properly address each cover letter properly! We are a bank and sometimes we get cover letters addressed to Hotels / Restaurants, etc. Goes to show that the person isn't detail oriented. Tsk,tsk.
My pet peeve would have to be applicants who I call up to schedule for an interview / take the exams sound uninterested, sleep (!) or annoyed. Once you submit your CV, I would want to assume that you really are interested in getting a job, so once you get a call and hear that it is from a potential employer, I think the least that one can do is to be accommodating. If for any reason, by the time you get that call and you are no longer interested, being polite is the least that you can do.
It is equally important to listen to instructions as well when you are invited for an interview. Certain companies are strict about the time or date or the necessary documents you need to bring. So when you arrive 15 minutes late, dear, you will definitely get a D- for punctuality especially for bigger companies where time is an essential factor because of the volume of applicants. There is a reason why there is a schedule given.
When you get to the interview, a good conversationalist will never fail to impress. NEVER. Giving one word answers like yes or no or maybe is a HUGE turn off. Worst, if you just nod or shake your head.
Come prepared.Before you even go for an interview, do a little research about the company you are applying for a job at. Being able to share what you know about the company is a sure sign that you really prepared for the interview and are interested in landing that job with the company.
Know what you are applying for. You can't go for an interview and just say that you are applying for whatever position is available. One's sensibility is highly reflected here. Your degree finished plus past work experience (if any) must match the position you are applying for.
Never say you want this job because you need the job. Who doesn't need a job? Focus on your goals and targets in life. Share your dreams and aspirations and how this job can help you attain them.
And lastly, smile,relax and be yourself.