1. Make youself as familiar as possible to your resume, so when you are asked about things related to your working experience, you can speak fluently.
2. Have a look at those "Frequently asked questions when interview", Answer and write down every question you may be asked, make youself familiar to those answers. It's totally different when you answer questions you have prepared.
3.Have a detailed study of their website. Learn as much as you can about their copany, people, products, technology,etc, especially those related to the work you will do.
4.Prepare some questions for them. It will be usually a pleasant thing for them to talk about their products. And it also makes you familiar with each other and ease youself a lot.

Good luck!