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 write to the employer, giving an additional 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.
If someone else also thinks you're great, give them a key role on your job search networking team.
Do not give in to the temptation of using a "fill in the address" prewritten 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.