Look at this really effective before/after photo thank you card. Bryan C. posts on this contractortalk.com threaddiscussing the value of referrals, this note: "I don't know if this would work for your line of work, but in the PW industry, customers love before/after photographs. I have incorporated this into our thank-you letters. I send a picture something like this that they then can show friends and neighbors and have gotten some good quality referrals from it."
This will cost you some money -- $49.50 per year (plus GST in Canada), but is worth every cent if you are in our service areas; or simply wish to see quality local construction industry journalism. You can subscribe (in Canada) to Ottawa Construction News or the GTA Construction Report or (in the U.S.) to Triad/Triangle Construction News or Charlotte Construction News (both in North Carolina). You can use this online subscription order form, or, if you perfer a personal touch, just email me at email@example.com