If you think influencer marketing these days means doing a one-off deal with a single big name who commands a eight-figure following on YouTube or Twitter, think again. These days, the average campaign by a big brand involves a fleet of influencers, 726 for an average campaign by a Top 20 brand, according to a study by InfluencerDB.

It's an astonishing number, at least if you aren't tracking the latest trends in the burgeoning business of influencer marketing, projected to hit as much as $10 billion in spending by 2020, according to MediaKix. And it's definitely paying off for some companies using these tools in the right ways, and for the influencers who can deliver for them. The key, as the industry evolves, is making sure you're hiring the right influencers, not just the most influencers.

The Wall Street Journal reported earlier this month that a handful of influence live-streamers on Twitch were paid as much as $50,000 per hour to play new video games around the time of their release. Ninja, perhaps the best-known of the lot, brought in $1 million to play Electronic Arts' new team battle-royale title, Apex Legends.

That's a pricey but highly targeted influencer spend that arguably paid off; Apex Legends hit 50 million downloads just weeks after its February release, outpacing even the record set by Fortnite,its biggest competitor.

But finding the right influencers among the sea of voices out there is becoming increasingly important, and complicated, for companies diving into influencer marketing. As "digital anthropologist" Brian Solis, a long-time author and consultant in the space, said recently, the business is finally beginning to grow up and get more sophisticated in how it uses influencers.

"What happened with the dawn of early digital influence, you would find people who have a lot of followers, trend against certain hashtags, put product in their hands and go," Solis said at the recent Open Influence Summit. "The reality is that’s no different than traditional advertising."

It can be easy to do what Solis calls "pay and spray" with dozens of influencers. But it's time that companies evolve their approach to what Solis calls "Influence 2.0," enlisting influencers who already are closely aligned with a brand's values and messages.

"You need to go looking for people who align with" your brand, Solis says. "What we live in today is too much noise, too much content. What people really need is help. (Influencer marketing done right) helps an influencer gain authority.  The brand becomes benevolent. If there’s reciprocity (in the value exchange between brand, influencer and followers), you become grateful in return."

A recent study of 2,500 influencers by Klear suggests that top-end "celebrity" personalities on average are paid $3,857 per YouTube video, and $721 per Instagram post. "Micro" influencers, those with between 5,000 and 30,000 followers, reap on average $908 per YouTube video and just $73 for an Instagram post, according to Klear.

So-called "nano influencers with less than 5,000 followers come at an even lower price, as little as $31 per Facebook post, $43 for Instagram, and $315 for a YouTube video, Klear said. That's not a big payday, for most influencers anyway, but it can provide some kind of income in a draining business that demands a frequent, regular online presence.

For those companies using these tactics at scale, influencer marketing can multiply impacts quite a bit.

InfluencerDB imputes a significant "media value" – what all those views, shares, likes, comments, click-throughs and the rest translate to in traditional media-buying terms – of more than $1.3 billion last year for the top five highest performing brands in its study.

Most of that media value, InfluencerDB says, accrued in the second half of 2018, perhaps a sign of accelerating brand interest in and embrace of the space.

The Big Five brands on InfluencerDB's list are an interesting mix of up-and-comers and established names in the $292 billion apparel business (ranked first to fifth in total media value, followed by "total likes in all posts mentioning the brand" last year:

• Fashion Nova (1.94 billion total likes)
• Gucci (1.02 billion)
• LikeToKnow.It (795.7 million)
• Zara (1.15 billion)
• Nike (788 million)

Fashion Nova is a Los Angeles company specializing in fast fashion, quickly copying hot design styles and creating their own versions. Not surprisingly, the company's marketing efforts rely heavily on influencers, and use social media to both prospect for new styles and drive awareness of their offerings. Fashion Nova's 2018 numbers were no doubt boosted by a November collaboration with star rapper and digital native Cardi B, as well as its first-ever line of Halloween outfits.

Aside from its robust online presence, Fashion Nova also has five brick-and-mortar stores in Southern California. It specializes in "club-friendly" clothes catering to a wide range of body types, including plus-size, curvy and maternity styles. It also has a men's clothing line.

Similarly, LikeToKnow.It lives online, though it offers a broader array of products besides fashion, including beauty goods, housewares, furniture, and athletic wear. LTK features a blog with interviews of online notables (identified by their online handles), including @nordicSH and @peonylim. The site recently launched a podcast, and has a presence in both the United States and Europe.

Zara, the Spain-based fast-fashion retailer, and Gucci, which sits a couple of steps higher in the fashion world's hierarchy, have also been smart about the ways they work with influencers. Nike is, well, Nike. Its roster of athletes is as powerful as online influencers as they are as on-field playmakers.