What are your expectations?  Times have not changed.  Stay top of mind with your clients past and present by using effective marketing practices.

It's all like fishing. You're sending the postcard marketing yourself by offering a service. You need to try several different postcards and see what pulls.

Whatever you do, do it consistently.  That's the key.  Offers for "what is your home worth" are often well responded to.  Share testimonials and recent nearby listings & sales.  Don't do it once and expect a huge result.

You nailed it! Each market is specific and what works for one farming area is a bust for another. Analyze the farming area.

A clear message along with consistency is key to being top of mind in any farming area.

The only post cards we have been sending out are for expireds.

We offer to help them determine why it may not have sold last time.

Most do not care why it did not sell last time and call us to let us know they are ready to get it back on the market and have read that we are the experts to get the job done.

In the end it is just a matter of letting them know you exist, they will then do the research and find out if you are the team for the job.

Make sure you have an online presence to sell this for you.

This question does NOT need to be anonymous, UNLESS it is being asked by a marketing / VA company wanting to sell good ideas to agents.
So I'll go with Free Market Analysis.
Come back with a profiles and suggestions that allow the agent to rise above the 'sea of smile faces' are more likely.

Consistency is the most important facet of a mailing campaign strategy.

I just reviewed something on a FB ad yesterday that was very well done. Now I can't rmember their name.

Wise Pelican

I send out post cards that are relevant to the market for advertising and also just listed and just sold cards.

Provide something they cannot readily get online.  Make it specific to their area, home, neighborhood, etc. 

Know your marketplace, some markets will respond and some will not.  One has to analyze where the fish are biting...A

No matter what you do, make it about THEM (and really them, not 'them-in-general) and be consistent!

I have sponsored my Zip on Nextdoor.com

being a people person has keep me busy for 30 years.  I stay in touch with past clients and have mostly a referral and past client business at this point.