I know an effective job posting trick that most people don't.
Ninety percent of the people who apply to a job posting on, say, Craigslist, will probably be wildly unqualified. The biggest challenge is to filter out the spam.
An easy way to filter out the spam, which no one seems to do, is just to throw up a Wufoo form with a few simple right-or-wrong questions. Basically, it's a micro-job-application. Instead of being frustrated that only 1% of respondents bothered to follow your application instructions and manually dealing with it by poring over emails, just require them to do it right by giving them a 4- or 5-field form. It's well worth the tiny amount of extra effort on your part.