There he sat, as expressionless as an iguana as I explained how an ad I would create for him would sink like a dropped anchor, even with a great headline, plenty of benefits and a no-questions-asked, money-back guarantee. He would be pouring money away with the tap wide open. It was a bit awkward for sure.

I recently sat eyeball to eyeball with a client that tasked me with finding a way to advertise a fish pizza that just hadn’t caught on. It was his “pet” pizza. He loved it. I thought it was okay, and customers had already been given free samples. Yet it just wouldn’t budge.

He figured some fancy ad would surely get this pizza moving up the sales channel and turn it into a signature item.

Let’s get straight on something right now: A deep-rooted, fundamental marketing “fact” is that you will make lots of money by selling people what they already want to buy. That said, you can go broke “on the quick” by plowing your ad budget into promoting fringe items with little interest.

Take, for example, grocery stores. They advertise top-selling items only. Stuff with wide appeal. Things with proven ability to drive traffic. Items that cast the widest net over the marketplace: milk, meats, soft drinks. They don’t promote mousetraps, toilet plungers or liverwurst.

I often see pizzerias advertise a “Large Cheese Pizza” at a low price-point because they’re afraid of scaring prospects away with a higher-priced offer. Now that’s fine if cheese pizzas are one of your top sellers. If they’re not, though, you are advertising something with little demand — and the low-price offer is costing you more than it’s bringing in.

Even though my pizzeria was widely known for “gourmet,” I found it best to advertise the Combo, BBQ chicken pizza, and I’d always throw a veggie pizza in the mix. Why? Because those pizzas made the phones ring off the hook. Now, I certainly listed my entire menu on most ads, but I only used photos and offers for my top sellers.

You’ll instantly improve your advertising results by following this path of least resistance. And that is by advertising what people already want to buy from you.

Here’s three easy ways you can figure out exactly what you should be advertising to drive the most traffic with the least money spent.

• What are your current top three selling pizzas or entrees?

• What has been a crowd favorite for a long time?

• What are the big chains advertising?

Okay, the mere fact that your top-selling pizzas are your “top-selling” pizzas means people want to buy them. Your marketplace has already told you what to advertise. Listen to your customers!