Also, if you're applying for the same field to different company, it would be very beneficial if you practice really well
As above, practice a series of answers to the different types of questions, based on what you have on your CV and put on application forms. Also look at adverts for similar jobs and see the type of qualities and experience they are asking for, and use that info too.
Don't rush into an answer; take a couple of seconds to take a breath and frame your response, making sure you are answering the question they have asked. If you don't understand something, ask for clarification.