If you really want the job, or if indeed you need to secure a second interview, the close of an interview can be crucial.  Think of the role of the interviewer, they are a liaison officer who aids an organisation in finding qualified applicants and selecting the wrong person will ultimately reflect upon their poor judgement.

Keep in mind the following:
Restate your interest and dedication to the job, remind the interviewer of your skills, credentials and relevant experience, which will positively contribute to the company.  However, be careful not to be over-enthusiastic.  Do not for example say “when do I start” this is being over presumptuous.

A person’s personality and style of communication are key factors to consider when arriving at a decision.

Enquire as to what is the next step, if for example, do they have several candidates to interview, or there is a second interview, some sort of time frame indication.

Perhaps ask if you are allowed to contact the interviewer – a direct telephone number or a business card providing contact details.

Whether any samples of your work is required, if you feel this could increase your chance.

Make sure you have addressed the interviewers concerns as you want to be certain all issues have been dealt with.  If for example, the interviewer has a negative view on a matter, state how you will overcome this, suppose you cannot drive – could there be a concern regarding travel?  Clearly explain that this will not be a problem.

Your main objective is for the interview to end on a positive note, remember to maintain eye contact and smile, as this will maintain a confident disposition.

You need to leave the interviewer with a lasting impression that you are the right person for the job.

Thank the interviewer for their time. 

Remember to send a thank you note for the interview because manners go a long way and if it is close between two people, this could just tip the decision in your favour!