Find the multis with deferred maintenance like high grass or fading paint and mail the owners a warm letter or postcard.  

I run an on-market real estate agent business and an off-market property acquisition business that discloses on all postcards that I have a real estate license.

I market (send postcards) to people who are behind on their mortgage payments, sometimes right before foreclosure.

And one postcard won't get results.

@Stephen Rivers I will send out 2 letters followed by 3-4 postcards.

I know that I want my first mailing to be all postcards.

For example, there are probably 100 other people in your market sending out a letter/postcard that says "quick close, cash offer, no fees, etc."

-Send a post card to the address (with the owners name) and the postal service should try their best to get it to the most current mailing address or the owner.There are tons of other ways, just get creative.

I have found that instead of sending on postcards to the entire neighborhood a simple colorful post card set to arrive at the 50 closest neighbors the day before the open house is very effective.  

Without pushing the listing contract, you can build some common ground and get a conversation that all the Realtors mailing postcards begging for listings aren't getting.