Prepare and practice. It is the best way to ensure a good interview.
Sell yourself - your skills and abilities. If you can do the job, say so.
Show your interest, flexibility and willingness to take responsibility for the job.
Be enthusiastic about the job and organization.
Avoid complaining about former jobs, bosses or personal difficulties.
Provide proof of everything you say. Don’t give one-word, or even one-sentence answers. Make sure you back up what you say with an example, story or proof of some sort.
Take time to understand the question and to answer it fully. When you’re done answering, stop talking!