I strongly encourage all real estate agent clients of mine to implement a "mail monthly, call quarterly" process for everyone in their sphere of influence, which includes all past clients and customers as well as anyone likely to generate referrals. In the interest of "going green" you might also consider emailing some of these monthly "mail" pieces.
To make the monthly mailings easier for you all, here are some suggestions to consider for each month. Where coupons or discounts are referenced, approach your local businesses and offer the opportunity to them to be promoted to your entire database, and most will leap at the opportunity to offer something for free, something at a discount, and they may even pay for the cost of postage!
January: HUD statement mailing for everyone who closed in 2008, and summary of 2008 market stats and activity for all; 'Time to change smoke detector batteries' reminder
February: coupon for a free rose from the local florist (thanks agent Janet Parsons for this idea!) or a free cookie from the local bakery to celebrate Valentine's Day
March: Happy St. Patrick's Day with a scratch-off lottery ticket enclosed (thanks Crockett Team); 'cabin fever' discount to local indoor miniature golf or bowling alley
April: Discount for spring window cleaning or lawn fertilization
May: Happy Mother's Day - offer a free Gerbera Daisy from the florist, or a discount for a family portriat at a local studio
June: Happy Father's Day - offer a contest where anyone who updates their email address with you is entered into a drawing for tickets to a baseball game
July: Independence Day! Agents Martha & Roddy McCaskill did a postcard that said "Baseball... Mom... and Applie Pie..." and offered a free slice of pie with any dinner purchase at a local restaurant. Or, send an American flag printed on the postcard for them to proudly display in their window. (Canadians, agent Bill Renaud used to do a Canada Day flag for his market)
August: mail school contact information (attendance phone numbers for all elementary and middle schools in your area), or football schedules for your local college or pro teams
September: discount for a furnace check-up and cleaning or winterizing the lawn mower
October: coupon to pick up a free pumpkin at your office; reminder to set clocks back
November: Agent Fraida Varah offers a free Thanksgiving pie (clients must call in to reserve their pie, so that Fraida knows how many to purchase); or send calendars for the coming year
December: coupon for a free or discounted poinsettia at a local garden shop; offer to come into the office on a particular day to have a picture taken with Santa