If you run ads on Facebook, then you know that the best way to earn a great return is to keep your Facebook CPM as low as possible.

If you're not familiar with the the acronym "CPM," it means "cost per 1,000 impressions." It measures how much you spend to get your ad in front of people.

Almost all advertising services offer reports that include CPM. Facebook is no exception.

Here are 6 ways to reduce your Facebook CPM and maximize your return on investment (ROI).

1. Target the Right People

The first thing you need to do to reduce your Facebook ad costs is to make sure that your campaigns are targeting the right people.

How does that help? Because when you run ads that appeal to your target audience, you improve your relevance score.

If you don't know about the Facebook relevance score, it's a term that lives up to its name.

The relevance score is measured on a scale of 1 to 10, with 10 being the best. It's very similar to the Google AdWords Quality Score.

And, in a nutshell, Facebook says that your relevance score can lower your ad costs:

Put simply, the higher an ad's relevance score is, the less it will cost to be delivered. This is because our ad delivery system is designed to show the right content to the right people, and a high relevance score is seen by the system as a positive signal.

Facebook lets you show your ad to an audience defined by demographics and interests. Underneath those two large categories are countless sub-categories that enable you to define a very tight audience.

If you want a decent relevance score, break your market up into segments (you probably have already done that) and run targeted ads to those specific segments on Facebook.

2. Watch the Frequency

Frequency measures how many times the same people saw your ad. You want to keep that number as low as possible.

Why? Think about it: when the same people are seeing your ad over and over again and not engaging with it, that means they don't find your ad appealing.

That's going to hurt your ad relevance. When that happens, expect your costs to go up.

As a rule of thumb, keep your frequency below 3. Once it starts going up to that point, it's probably best to change the ad or pull it completely.

3. Use an Attention-Grabbing Image

In case you've missed the overarching point here, it's this: the more people engage with your ad, the lower your overall ad cost. One of the ways that you can get people to respond to your ad is with an image that stands out.

Find or create a great image that relates to your ad. Then, think about a way that you can create that same image so that it stands out from the standard set of graphics displayed in a typical news feed.

And, as always, make sure that you follow Facebook's recommendation and use an image that's 1,200 x 628 pixels.

4. Include a Call to Action

Facebook offers you many choices when it comes time to add a call to action (CTA) button on your ad. Although you don't have to use one, you should.

Why? Because one of the best ways to get people to engage with your ad is to ask them to engage with it. A CTA button will do just that.

Facebook allows you to select CTA text such as:

Shop Now

Book Now

Learn More

Sign Up

If you're not sure which option to select, go with "Learn More." That's the least "committal" of the choices and some people think it generates a higher CTR.

5. Add Social Proof

You might think that social proof only belongs on your website landing page. Think again.

Social proof belongs on your Facebook ad. It will increase engagement just as it does anywhere else you include it.

Add your social proof in the "Text" area where you have some extra room to add more detail. Include something that will resonate with your target audience, such as:

A celebrity endorsement

Quotations from satisfied customers

A list of businesses that use your product or service.

6. Run Ads in The News Feed

If you want to maximize your engagement, it's probably best to keep your ads confined to the Facebook news feed. That's especially true if you're just getting started.

Let's face it: the news feed is the reason Facebook exists. That's where most users devote their attention. 

If you want to maximize your ad visibility, put it in the news feed.

You can run your ad in the right-hand sidebar, but that position doesn't get much attention. You can expect ads in that spot to receive less engagement.

And, of course, that means your Facebook CPM will increase.

Getting Started

When it comes to ads on Facebook, not only are there a lot of targeting options, there are also endless types of creative to test.

These 6 points will get you off to a great start. But you will have to keep working, testing and refining to stay profitable on the platfomr.