(Joe Raedle/Getty Images) Once you leave the interview, there's one more important step to take.

You spend weeks preparing for a job interview and give 110% once you're in the hot seat. You walk out feeling confident and relieved — like your work is finally done.

But it isn't.

In fact, there's still one more crucial step to take if you really want to land the gig: sending a follow-up letter.

"The best timeframe to send a thank you email is within 24 hours after your interview," says Whitney Purcell, associate director of Career Development at Susquehanna University. "It should be sent during business hours – no 3 a.m. emails that make your schedule seem a little out of whack with the company’s traditional hours."

And note: A simple "Thanks for your time!" won't do. You need to really "wow" the hiring manager and make a great final impression before they make a decision about you.

Your follow-up thank you email (yes, experts say most hiring managers prefer email over hand-written notes) needs to stand out from the crowd. It should highlight the best parts of the conversation you had with the interviewer, and a final reminder as to why you'd be perfect for the job.

Dr. Deborah Good, a professor at the University of Pittsburgh Katz School of Business, says the following is an ideal follow-up letter because it possesses six important traits: