A number of years ago, I consulted for a well-known charity, writing and designing fund raising emails. This organization had a strong marketing program and a loyal base of supporters. We were always racking our brains to come up with some new and clever way to ask the group's donors to make one more contribution.

Donations to this charity are tax-deductible, and every year, one of our top performers was this: In late December, we'd send an email with a simple headline along the lines of "Only 48 hours left to claim a tax deduction on this year's tax return." It never failed to bring the donations rolling in.

So here's the interesting thing. In surveys, the group's donors told us they didn't actually care much about that tax deduction.

The moral of this story is that deadlines deliver dollars. You see, the tax deduction didn't motivate people to make their donation — but the deadline did motivate them to do it today!

When you're in the marketing business, procrastination is one of the big reasons that campaigns fail. For everybody who responds to your message and whips out their checkbook, you can be sure there are others who mean to, but just never get around to it.

Once you tune in to how much money you're losing to donors and customers who procrastinate, you'll understand why marketers across the spectrum are always urging you to "act now" before you miss some deadline. Here are three tips for making the most of deadlines to overcome this human habit of procrastination:

Deadlines usually mean "deal." You have to give your audience a reason not to miss the deadline, and most of the time that means getting more for their money somehow. Two for one if you act before Valentine's Day. Our anonymous donor will match any gift you make until his birthday next Thursday. Free shipping for the first 100 customers.

The deadline must seem real. Deadlines have much less punch if your audience senses that you made them up yourself. They have more punch if somebody else imposed the deadline. For example, Uncle Sam gives you until Midnight on December 31 to claim that tax deduction. Valentine's Day is February 14. We've only got 10 widgets left and when they're gone, they're gone. You get the picture.

The deadline must be coming up fast. In your marketing campaign, you want to give people enough time to meet the deadline — but just barely. For an electronic donation or purchase, two days is a good amount of time. If it's an impulse item and they're already in your store ("Attention K-Mart shoppers"), the you can give them just a few minutes. But if you want to sell them on a big ticket item (that involves negotiation with the spouse), then you better give them a week or two. But however long the deadline it is, it should seem like it's coming up fast. Any longer defeats the purpose of having one in the first place.

It's strange but it's true — one way to make more money is to give people less time to spend it! So the next time you are planning an advertising or fundraising effort, give some thought to how you create some kind of deadline, a sense of urgency of that helps helps your audience stop thinking "I'll do it someday" and start thinking "I'll do it today."

Eric Eckl helps nature protection and pollution control organizations raise environmental awareness. He writes the water blog, Water Words That Work, to dispense tips for planning and carrying out environmental fundraising, issue advocacy, and behavior change campaigns.