If you have been invited to interview it means that your application/CV has convinced this prospective employer that you are a real contender for the job. Interviewing is expensive in terms of staff time and money, so employers are not going to waste either on unsuitable candidates.
Having said that, you need to do more to secure the job, and the key to interview success is preparation.
You have probably already researched the company to get this far, but you need to refresh your memory and perhaps do further research. If at the interview it is clear you don't know much about the company, the employer is likely to question your commitment to the job.
Team player, good listener, organised, co-operative, motivator, friendly. Having a part-time job, doing voluntary work, playing for a team and being a guide/scout leader would help build good people skills.
You also need to prepare yourself. Certainly until you have had some interview practice it is not enough to just mentally prepare how you might respond to particular questions - you need to practice the answers out loud.
Remember that body language is important. Try to smile when appropriate, e.g. when being introduced to the interviewer(s). Leaning slightly forward when answering suggests enthusiasm whereas lounging back does not.
For more information about types of interview, preparing yourself, making an impression, interview questions, interview problems and job offers see Interview tips and Interview tests and exercises on our desktop site.