There is a step you can take to make a lasting impression after your interview and greatly increase your odds of an eventual offer.
You need to immediately write the interviewer a short note, thanking him/her for the time and re-emphasizing your interest in the position. Then do your best to get this note to them as quickly as possible. Email it (preferred), hand-deliver it, messenger it, use overnight mail, whatever is fastest. But be sure they have it before the end of the following day. Ideally, you want to get it in their hands by the end of the day of the interview or first thing the following morning. Why? Because the quicker your note arrives, the greater the likelihood of effecting a positive outcome. Doesn't everyone follow up like this? No. Only a few take the time to write a personalized "thank you" letter. The simple gesture of a thank you note can make a big difference in separating you from your competition.
And if you interviewed with multiple individuals, make sure each thank you note is unique. Common language is acceptable, but do not simply change the name at the top of the letter. Your application, resume, and other materials will likely be stored in a single file, usually in the possession of the person guiding you through the hiring process. Your thank you notes will eventually find their way back to this central file. Yes, recruiters do compare notes. And what seemed to be a unique and original note can lose its impact if there are two or three duplicates collected together in your file. It has taken a great deal of effort to get this far. Take the extra time to make this final impression a positive one.
If you want to make a lasting impression on a potential employer, ask the individuals who supplied you with letters of recommendation to either call or email the employer, giving their recommendation. This technique will instill confidence in the employer that they are making a wise decision in hiring you.
Obviously, this technique works for you only if you have a strong sponsor (or two) among your references. And it has the potential for abuse—you do not want to burden your reference in every interviewing situation. However, when you truly believe "this is the one," it may be time to cash in some chips.
Do not give in to the temptation of using a workaround "fill in the address" prewritten email or letter from your reference. It should be unique and original. This technique works because it shows that others think highly enough of you to take the time to call or write. There is truly no higher compliment your references can pay you. So remember to thank them—in words now, and with a card and a small gift when the offer comes.