How I can get over my nervousness when I go for an interview?
Being nervous at a job interview is very common. There is nothing to stop you telling an interviewer how you feel at the start of any interview; it can help to break the ice.
An honest start to an interview will not go astray.
Nervousness is a clear sign that you want to do your best and good preparation will help you considerably. Find out all you can about the business and the job beforehand. Practise your interview the night before by making up your own list of possible questions and considering the answers. You will find your questions and those you confront the next day will usually be very similar.
At the interview, take your time in answering questions. Give yourself at least four to five seconds between the question finishing and when you start answering. This gives you time to consider the question and collect your thoughts. It does work.
Be yourself and trust yourself. Most times the right person will win the job and, hopefully, it's you at your next interview.
Source: http://content.mycareer.com.au/advice-research/interview/interview-nerves.aspx