It can’t always be a good idea, but when it’s right, this could work well for you:
Introduce Yourself When They Aren’t Looking
What if you saw an ad for a job where you knew there was a fair amount of turnover. To add to this, let’s assume you are not desperate and unemployed. Wouldn’t it make sense, then, to allow the ad to run its course and send a letter a few weeks later to make it appear your interest in the company was genuine and not an opportunistic spur of the moment decision made because there was an enticing ad that sparked your interest? The point here is to get yourself noticed when they aren’t looking — and when there aren’t a hundred other candidates seeking their attention all at once.
The other seven ways are pretty good too: read the full list. (And a nod of the hat brim to Lifehacker for spotting this.)