A Guide to Working With Instagram Influencers: What to Look For Are sponsored posts disclosed? You work with deceptive influencers at your risk.

When you're looking to build buzz for a product or service, working with digital influencers like popular Instagrammers can help you reach your goals.

Related: 7 Marketing Tips to Help Grow Your Brand on Instagram

According to a study by Nielsen and TapInfluence, influencer marketing drives 11 times more ROI as other forms of digital media. How is that possible? Well, unlike Google AdWords or banner ads, influencer content stays online long after a post has faded.

For example, in February 2017, beauty influencer Estee LaLonde posted a photo promoting the new Burt's Bees lipsticks. When the video first went up, it received about 5,000 Likes. Today, that content still sits on LaLonde's Instagram page, where to date it's received more than 11,000 likes.

Since working with influencers is such an effective form of Instagram marketing -- and digital marketing in general, -- here's what you need to know before putting together your first campaign, especially the questions to ask yourself (and the influencer) when searching for the right influencer to work with:

1. How often are new posts published?

While many of us don't have the time to post to Instagram every day, let alone multiple times per day, it's the job of a digital influencer to post frequently. According to recent research, social media frequency across the board should look like this:

• Pinterest: five posts per day

• Twitter: three posts per day

• Facebook: two posts per day

• Instagram: one post per day (or more)

Since you're looking to work with a popular Instagrammer, you should focus exclusively on that person's frequency in posting to Instagram.

If you see an influencer with a million followers and his or her last Instagram post was over a month old, steer clear of that person, as s/he is not actively engaging his/her audience on a daily basis. This is usually a sign that the influencer has moved on to do other things and no longer has a strong relationship with that audience.

Related: 9 Top Social Media Influencers Marketers Need to Follow

2. Is there an over-abundance of sponsored posts?

An influencer whose feed is full of sponsored posts is also one you'll want to avoid. While there is no hard rule about how often an influencer should share sponsored posts, sharing too many can reduce credibility with the audience.

The reason is that followers of an influencer are interested in that person's honest opinions about products and services. Adding payment to the equation can affect the integrity of a product review. The audience may begin to wonder, "Is he/she saying this only because of the pay?"

Digital influencers who have built up a strong relationship with their audience do so only by working with brands they really like, and by spreading out the frequency with which they promote sponsored items.

3. What is the engagement rate?

There is a common misconception that the more followers an influencer has, the better it is for the brand. Unfortunately, spam or fake followers can be purchased, inflating a person's audience size without increasing his or her influence.

When evaluating digital influencers, look for both the size of their following and their engagement rate. You can calculate an influencer's engagement rate using this formula: (# of likes + # of comments) / # of followers.

Engagement rate benchmarks vary by age, industry and follower size but generally fall in the 4 percent to 8 percent range. Be wary of paying an influencer whose engagement rate falls below 4 percent.

4. What other brands have sponsored posts?

Finding an influencer who will be able to make an impact for your brand means making sure that person's content reaches your target audience.

If you're not already familiar with digital influencers in your category, ask which brands the influencer has worked with in the past. Have any of your competitors worked with this influencer? If so, request to see how well those sponsored posts did. Were there many likes, comments, shares and views, or did the content seem to fall flat?

If the content did really well, you'll probably be wise to work with that influencer. You'll just want to make sure enough time has elapsed between when your competitor's post went up and when your post goes up. After all, if audience members just purchased your competitor's product, they may not be interested in spending money on a similar product at this time, no matter how much better your product is.

5. Are sponsored posts disclosed?

The FTC offers guidelines for digital influencers when it comes to accepting sponsorships. The general rule is that disclosure should always be made when accepting money or in-kind gifts.

While there is technically no fine for violating the FTC's guidelines for nondisclosure, it is important that you work with influencers who have a good relationship with their audience. That means that their followers trust their product reviews and believe them to be accurate.

When influencers frequently fail to disclose sponsored posts, this may affect their credibility with their audience, thereby reducing their influence.

You therefore work with deceptive influencers at your own risk. But my suggestion is to work only with professionals who know and comply with the guidelines of their industry.

Getting started

Now that you have a guide to help you find the right digital influencers to work with, it's time to get started. You can begin by reaching out to the influencers you're selected via their publicly published email addresses or through their management team.

Related: 4 Easy Tips on Executing a Flawless Influencer Campaign

The best influencers will make this contact information readily available, as sponsorships are their main source of revenue. If you can't find contact information, take that as a sign!