Hopefully, you’ve taken the time to take a close look at the REAL demographic data within your client list. Unlike many businesses, you have a wealth of this sort of data on your clients, simply because of the nature of what you do.
So what do you do with it?
Last week, I said “profit”, and it’s been pointed out to me (rightly) that this was, oh … a little vague:).
So, let me expand on this with a few ideas for you:
1) Create a demographically-targeted mail SEQUENCE, clearly-identified as “for” the particular demographic group which already represents your most-profitable client-type. This may seem like a “duh” concept, but I’m continually amazed by the lack of segmentation and the lack of a specific flag for the recipient to think: this mailer is for me! You can simply use a headline: “Attention: Day-Care Business Owners — You May Be Losing Thousands of Dollars in Revenue Due To Using The Wrong Business Entity!” or “Attention: Dentists — Our 17 Dentist Clients Don’t Want You To Know Their Tax-Planning ‘Secret Sauce’ (But You Don’t Have To Tell Them We Told You!)”, or some such.
Do you see how this is different from a traditional, “business-card-style” mailer? Those aren’t even worth the paper they’re printed on, so there’s a reason why they haven’t worked for you in the past.
2) I mentioned “sequence” above: Do not just send “one” mailer! Think about how often you respond when you receive a “cold” letter from someone you don’t know … and try to get past the sense that of course they’ll be falling all over themselves to call me! This is why it’s such a good idea to have an effective social media presence plus a system to build relationships over time with your prospects.

But to the task immediately at hand: you can simply re-purpose your first piece, and add “Second Notice” to the top, and get your prospects to take action.
3) Have a deadline and a clear call-to-action. Don’t just assume that your prospect will respond, unless you give them a REASON to do so — with teeth. Whether that’s a limitation on initial evaluations, or a date after which they don’t get a bonus … give them a good reason to say “maybe”.
I hope this helps. I’ll be in closer touch again next week.
To You and Your Family’s Peace of Mind!