Preparing for technical round Interview is bit different from all other interviews. It totally shows your working ability and dedication for technology, problem solving ability and Technical skills. Here, few things are listed that can help you to prepare yourself better.
Research: Find out what the company is looking for and prepare accordingly. For this you can look in to the products or projects the company is currently working on, the eligibility criteria posted for candidates etc.
Study: Once you know the requirements of the company, refresh your knowledge of the related fields. If you are invited for the interview, you can assume that that some or all of the requirements of company are mentioned in your resume. Put special focus on the skills or technologies that you have mentioned in your resume and that you think the company would be most interested in.