Questions are about 80% situational and the rest are based on your previous work experience. Think of specific examples and previous projects you've worked on to reference. Know the job that you're applying for well and make sure you keep your previous work experience relevant to the job you're interviewing for. Ask them your own questions at the end.
Know the job you are applying for and have all of the information needed to answer their questions. Also, have questions of your own for them.