The interview doesn't end when the interview ends. 

Follow up with a thank you email or letter within 24 hours of the interview. In the thank you letter, include the skills you discussed and underscore the reasons that you would be a good fit for the position and company.  Stay on the interviewer’s radar and call or email to follow up as to the hiring decision. This is your chance to stand out from the crowd and reinforce what makes you the best candidate. Keep your momentum - continue your 3P's with another employer in mind. If you get the job - GREAT! However, if you don't you will be ready to land your next interview.