Robert Williams has compiled a nice and valued list of advertising executive David Ogilvy's 20 rules for getting and keeping clients.

6. Only accept a client if you can improve their existing work.
Ogilvy was famous for turning down the New York Times because he "didn't think (he) could produce better advertisements than the brilliant ones they had been running." Don’t think you can create better work than what's already there? Don't take on the client.

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10. Avoid contests in which more than four other agencies are involved.
It's way too easy to waste your time in meetings. Especially when you're on the shopping list of every prospective client. You have other fish to fry — the fish of your current clients. Ideally you wanted to be courted by clients who have no other prospects in mind.

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13. Tell prospects about your weaknesses.
David picked this up from antique dealers. He realized that when a dealer drew your attention to a flaw in the furniture, he almost always gained your trust. If you do this too — before the client notices your flaws on their own, you will also gain their trust. It will make you more credible when you boast about your strong points.

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15. Explicitly tell clients why they should hire you.
The day after a new business a new client meeting, David would send the client a 3-page letter on why they should pick him. Today you can send an equally brief email to help clients make the right decision.

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20. Use what you specialize in to find new clients.
David Ogilvy created ads selling his ad agency. You should dog-food your own service too. So how does your work help clients? Can it help you in the same way? For example, do you help them find customers by creating content? Create content for your agency. Do you do graphic design? Create infographics for potential clients. The trick will be to not just make thing that you like or impress people in your industry, but to make things that impress potential clients.

I own a hardcover copy of Ogilvy's "Ogilvy on Advertising" (1985) that I highly recommend.

Image credit: Ogilvy & Mather

Via @TheDesignTrust.