If you're looking to build anticipation for an upcoming product launch, or generate brand awareness with a niche audience, now's the time to consider influencer marketing.

Partnering with social media stars isn't just a vanity play for brands; influencer marketing can actually deliver a serious return on investment. According to  RhythmOne's Influencer Marketing Benchmarks Report and Guide, marketers who implemented an influencer marketing program in the first half of 2015 received an average of $9.60 in earned media value (EMV) for every $1.00 spent--an increase from $6.85 EMV per $1.00 spent in 2014.

Working with influencers, however, is not without its challenges. While some established social media celebs have evolved into highly professional brand marketers, others are still very much learning the ropes. A lack of knowledge or a less-than-collaborative attitude could undermine the success of your campaign.

Before entrusting an influencer to do an Instagram takeover or live tweet your event, ask her these 6 critical questions. 

1. How do you relate to my target audience?

Don't be afraid to cast a wide net when choosing an influencer for your brand. Many brands make the mistake of limiting their search to on-the-nose influencers representing their space.

Instead, think about which non-endemic verticals your target audience cares about. That's how design brand  One Kings Lane found success with its "Reflect Your Style" initiative, in which it seeded mirrors to fashion and beauty bloggers including Comfy Cozy Couture, the blonde prep, and  The Lady Olive.

Use your knowledge of your target customer profile to get creative with how you reach them.

2. What is your typical response time?

You can tell a lot about what working with an influencer will be like by how they react during the vetting process. Are they positive, collaborative, and easy to reach? Or are they indifferent, inflexible, and slow to respond to e-mails or calls?

If it's the latter, remember that communication rarely improves once the contract is in place. At our editorial marketing company Masthead Media, we've found that it's a lot easier and more pleasant to work with a well-vetted up-and-comer than an overextended veteran--and the quality of the work is often better.

3. Are you able to report your analytics?

Unless the answer to this question is an unequivocal "yes" accompanied by proof (such as a screenshot of Google Analytics for blogs, Page Insights for Facebook, or Iconosquare for Instagram), you probably don't want to enter into this partnership.

You absolutely need these metrics in order to measure the social engagement and success of your influencer initiative and, ultimately, prove your ROI. Save yourself a struggle later by including in your contract a clause requiring influencer partners to provide analytics before they are paid in full.

4. What were your most successful brand partnerships?

Request examples of branded work an influencer has completed in the past year so you can get an idea of how his platform allows for brand integrations.

This is also a great opportunity to see analytics in action, so ask for performance numbers as well. Compare the success of past branded posts with average post views. Do the numbers seem low? Dig deeper to find out why.

5. Are you comfortable with these deal points?

Outline all of your expectations for the campaign and individual posts, and make sure everyone--particularly the influencer--understands the details.

These may include how many tweets an influencer uses to promote a branded post, how many times the brand must be mentioned per post (and any required language for posting), how high up in a blog post a link to your product should be, if the influencer will respond to readers' comments, and when they will deliver analytics.

Negotiate for what your brand and campaign need to be successful. Don't be afraid to walk away.

6. What is your "emergency" contact information?

When assembling a contact grid for your influencer campaign, remember that emergency contact numbers may vary from primary points of contact if you are working through a management firm or other intermediary.

Because influencers post on nights and weekends, you need an after-hours direct contact number so you can quickly correct any mistakes.