Ever spot a photo with the #ad or a “paid partnership tag?” Then you’ve seen the results of an influencer marketing program. Companies pinpoint digital influencers who have followers that match the brand’s target demographic.

Armed with free products, influencers are paid to create and post content promoting the brand, resulting in brand awareness (and hopefully) sales.

In 2017, influencer marketing grew 198 percent, found Klear research. That’s why at the end of last year, 39 percent of marketers stashed away more money to spend on influencer marketing, according to a Linqia study. It helps that nearly all marketers (92 percent) who used influencer marketing in 2017 found it effective, according to recent eMarketer research.

If your business, too, sees influencer marketing as a pathway to success, consider these five points first.

1. Go for Instagram

Most influencer marketing happens on Instagram. It’s by far the most requested platform for influencers to post branded content, according to a 2017 Everywhere Agency survey.

Instagram’s users also skew younger. 53 percent of 18- to 29-year-olds are on Instagram. That’s more than 5 times the amount 50 to 64-year-olds there, found 2014 Pew Research.

It does help that millennials are very affected by influencer marketing. 70 percent of Millennial consumers are more likely to purchase a product when it’s endorsed by a prominent blogger, found a 2016 Collective Bias study.

If your audience isn’t in this demographic (or on Instagram), influencer marketing may not be your best bet.

2. Pinpoint ROI

Before you pick your influencers, first, plan how you’re going to measure the program. 76 percent of marketers said determining the ROI of their program would be their biggest marketing challenge, in a 2017 Linqia study. Most marketers measured engagement, followed by clicks, impressions, conversions, reach and product sales.

Sales and conversions driven by influencer marketing programs can be strong. For every dollar invested in influencer marketing, you get, on average, $6.85 in returns, according to Burst Media research. While tracking these metrics is more difficult, it can be more worthwhile to prove the worth of your program.

3. Think small

You actually don’t want to pick the influencer with the biggest social media following.

Instead, select individuals who have a modest social follower base (at least 10,000 but no more than 100,000). Their rates are going to be much more reasonable (between $100-500).

Plus, those influencers are going to have the time to really engage with their followers, which makes a big difference. Their followers will feel they have a friendship with that person, which means they trust and value their opinion on recommendations more.

4. Give them creative freedom

Only 13 percent of micro-influencers said that brands gave them enough freedom to create totally authentic content, found a 2016 Collective Bias study. We’ve got to do better than that!

You choose your influencers because you admired their style and trusted their voice. So, let them do their thing. More authentic content always performs better, so set them (and you!) up for success.

5. Keep talking

After you’ve put in the hard work and found the right influencers for you, keep working with them. Many brands do a one-off influencer marketing campaign. But that isn’t going to be as effective as a sustained campaign.

To really make an impact, keep working with that influencer, month after month. By staying top-of-mind with their followers, you’ll win them over slowly, but surely. This tactic is a must if you’re focusing on conversions or sales.