@Mary Newman Guy buy the Dsn Kennedy "Magnetic Marketing" book or, better yet, the $297 course. 

I agree with @Kevin Fox that it is all about location, with the right location you could easily have 20-30 applicants and others will be vacancy magnets.

I think you'd be better off having your postcards target renters who are thinking/looking to buy a house, rather than find a new apartment to live in.And, you could create a free Home Buyer's Guide and offer that as a lead generation magnet, to get renters to give up their contact info in exchange for the guide (that way you'll be able to follow up with them).I personally don't see your current plan working, but I could be wrong.If you have the money to invest, then test-Test-TEST.Also, if you go through with it I'd love to know how it works out for you.

Magnetic pole shift.

I just did something similar with the AmEx cash magnet - 0% for 15 months and 1.5% back. 

Motivations Magnetism Motivation is sexy.

I have multiple running, but one that has worked more than I expected it too is making a sticker magnet and placing on the side of my car.

It is a magnetic place, and the community is hard to beat.I guess I think of it as akin to buying a Class A share of Berkshire Hathaway.

You can also put large magnetic signs on the sides, to advertise your real estate business.

Or the off-market deals—not the fake off-market crap that is simply using the “off market magnetism” to find a sucker for an overpriced property, but true off-market stuff that only comes to you if you have a proven track record with the broker.Over time you will develop these relationships but you’ll have to close a few more deals first.