It takes more than just the ability to write great stories to build a $15 billion brand. J.K. Rowling, the best-selling author of the ​Harry Potter series, knows the secret to maintaining her success: Keeping her fans  loyal and  engaged

On Tuesday, Rowling published the first installment in a series entitled History of Magic in North America on The proprietary e-book website accounts for a considerable chunk of her reported $13 million of earnings in 2015, according to a Forbes estimate. 

The series is a walk-up to a new film she penned, Fantastic Beasts and Where to Find Them, which stars Eddie Redmayne (Theory of Everything, The Danish Girl) and is set in New York in 1926.

The idea behind the series is to give readers context about what the "wizarding world" looked like between the 14th and 17th centuries in North America. On Wednesday, Rowling released the second chapter in the series. She'll continue to release a new chapter every day this week. 

Unfortunately for the writer, not all fans have been especially pleased with her new work. In particular, Native Americans have taken issue with Rowling's take on the Navajo "skin-walkers" legend, and are accusing Rowling of cultural appropriation.

"It's not 'your' world. It's our (real) Native American world. And skin walker stories have context, roots and reality... You can't just claim and take a living tradition of marginalized people. That's straight up colonialism/appropriation," tweeted Dr. Adrienne Keene, an activist and author of Native Appropriations, a blog that addresses pernicious stereotypes of Native American communities.

Rowling has not yet responded directly to critics including Keene on Twitter, which analysts note is atypical of the author's social media strategy.

"That's unusual," said Libby Turner, a director with the digital marketing agency Room 214, who follows Rowling on Twitter. "I think she really wanted the story to be released and let people make their own assumptions, rather than engaging with them before they had all of the information."

In this instance, Rowling may have offended many. But she certainly has a reputation for being engaged with conversations that surround her work. Since joining Twitter in 2009, the author has posted over 3,000 tweets, amassing 6.95 million followers in the process. 

She also retweets from a variety of sources, shares thoughts on current events, and generally makes a point of responding individually to reader comments.

Here are five of Rowling's best social media practices that startup founders should consider emulating.

1. She uses Harry Potter as a lens for social commentary.

Anyone who follows Rowling on Twitter knows she isn't afraid to voice an opinion. What's more, she often couches it in a reference to Harry Potter, which is, of course, the staple of her brand. 

"She uses the Harry Potter series as social commentary for what's going on in the world," said Laura Oxler, a digital producer with Room 214. On one occasion, for example, Rowling compared Donald Trump, the  current front-runner for the Republican presidential nomination, to the evil character Lord Voldemort: 

She recently retweeted the account @VoldemortForMayor, which nods to the controversy surrounding gun control and the right to bear arms: 

Similarly, after announcing that one of her major characters, Hogwarts headmaster Albus Dumbledore, was gay, Rowling responded to an inquiry over Twitter:

The user who posed the original question ("I wonder why you said that Dumbledore is gay because I can't see him in that way") has since deleted her account.

2. She posts frequently.

For every original piece of content on Twitter, Rowling sends out about 15 to 20 responses to her fans.

"That's the cadence we like to see with any company," says Turner, who gathered the data. After all, a growing body of research suggests that Millennials crave authenticity--and social media is one of the best ways to show your customers that you care.

Consistency, she adds, is an essential key: If you tweet four times in a single day, and then don't post for weeks on end, your audience may get the sense that you can't be trusted.

3. She does her research, and communicates elegantly.

When Rowling responds to a fan on social media, she typically has a well-crafted and creative answer. Consider, for instance:

Although young readers obviously don't spontaneously cast spells, this does nod to the real world psychology of development.

"When people experience the world in child mode, they feel powerless and at the mercy of others as well as overpowered by their own feeling reactions," psychologist Robert Firestone wrote in Psychology Today. 

"In the actual world of the child, the child is helpless and totally dependent and is often the victim of negative circumstances that are beyond his/her control," he continued.

And it never hurts to pepper in some humor--especially when it is done effortlessly, a form that Rowling has clearly mastered:

4. She's fearless.

As a business owner, you run the risk of alienating your customers by taking a strong political or social stance. Still, digital analysts advise that on social media, it's important to develop (and stay true to) your personality, even when it means pushing back against the status quo. 

"We talk to our clients about what their tone of voice or personality is like on all social platforms. She [Rowling] is an amazing example in that she knows her voice, she knows who she is, and she also researches and has a lot of intelligence with how she approaches everything," Turner says.

"Regardless of whether you're on the wrong side of that pushback, I think it creates this trust and this respect that is really hard to alienate people with," she adds.

5. Remember: At the end of the day, it's still marketing.

Ultimately, Rowling is a master marketer.

In addition to baking in references to her original series -- through which she continues to make money -- she also makes a point of promoting new projects, such as the four essays, her upcoming play, Harry Potter and the Cursed Child, as well as the film Fantastic Beasts and Where to Find Them.

Still, her marketing is beyond clever. The secret, according to many analysts, is that she understands the balance. Rowling never goes overboard.

"The cool thing about J.K. Rowling is that she isn't advertising, she's not hitting people over the head with things they don't want to know," says Turner.

She advises that before you try to sell a brand or service, it's important to figure out who exactly your target is--especially on social platforms like Twitter. Once you've tracked down that core audience, find out what your product actually means to them.

"This is really a case study for how you can build a world, build a story, build a place where people really want to spend time and engage with you," says Turner.