I agree with waiting around at the airport, but some of us need to pay mortgages and can't afford to wait around 6 days a week like a 22 year old fresh outta UND living back at his/her parents' house. Therefore, we must find a balance between spending time at the field at the "targeted marketing" as mentioned earlier and maybe working a second job.
After meeting anyone for the first time, ALWAYS promptly hand over your business card after you've shaken their hand. List the normal info on front, and put a copy of a flight plan on the back. Kinko's can pump it out in an hour. Print it on heavy paper, and they'll be FORCED to carry it with them, as we always lose those dang flight plan sheets.
It might sound cheesy, but there's this great video AOPA put out about recruiting students. Basically it says that you have to sell the idea of "challenge and adventure" when you're talking to potential students. If you're an AOPA member the link is:
http://flighttraining.aopa.org/cfi_tools/
The only other thing I've done to snag students (over other CFIs in my position) is to tell potential students that I am accessible 24 hours a day and am free to answer questions over email or by phone (no ground charged...within reason). Many CFIs treat the job like a 9-5 job and could care less about students after they've gone home. But the offer of accessibility makes the student feel more valued.