There is an abundance of free material on interview preparation available from reputable sources online but the key thing is to prepare thoroughly. At the very least you should..
Have a good understanding of what the company are looking for and why you are the best person for the job. Keep it relevant and make sure you have prepared a few examples, substantiating why you are the person they should hire.
Be able to talk about your strengths and weaknesses, why you want the job, what you will bring to the role/company and your career development to date, including why you moved on from previous employers and your career aspirations.
Research the company and their markets. Start with but don't limit your search to their website.
Prepare a few insightful and relevant questions, that reinforce your interest in the role and that you have done your homework.
Finally, make sure the logistics are covered and that you arrive 10-15 minutes before your interview is scheduled to start, with everything you need to hand (did they ask you to take a portfolio along for example or perhaps they requested you take your passport) and looking your best, calm, composed and relaxed!