If you feel an interview went well and you want the job, be sure to end the interview on a positive note. As you are wrapping up the conversation, thank the interviewer for his/her time and reiterate that you are very interested in the position:

“Thank you for taking the time to meet with me this afternoon. I really think my background is a strong fit for this role, and I look forward to continuing the process.”
- or -
“Thank you for taking the time to meet with me today. I am now even more excited about the opportunity to join your group; I think my experience is a strong fit with your needs. I look forward to hearing back from you.”

Bottom line: an interview is not successful (on your part) if the interviewer comes away liking you as a candidate, but questioning your interest level in the position. Don’t leave anything to chance—especially in this job market. If you want the job, be sure they know it!