Here's a free marketing idea for my friends in the architecture field. The inspiration came from United Health; as part of their member outreach they send a birthday card to all their members reminding them of the preventive screenings they're due for that year.
Here's my twist for the architectural community. As part of your CRM (define) program send a birthday card (or perhaps an anniversary card) to your clients each year to commemorate the completion of the building your firm designed for them. It will remind them to reflect on the joy your firm's design has given them over the year(s) and keep your firm's name top of mind when they're considering other design projects, or speaking to friends and colleagues who might be looking for an architect.