Close the Interview
All things being equal, people hire people who want to work for them. You should close (at end of the interview) with:
Mr. / Mrs._______________, I want to thank you for the time you have spent with me. I know I can handle the job and make a contribution to your company. I'm very excited about this opportunity. Do you have any questions or concerns about my ability to do this job? At this point if they do have doubts, this will allow you the opportunity to alleviate any concerns, just or unjust, that they may have. Then, "What is the next step?"
Show enthusiasm and genuine interest.