Artist's use of media

How Taylor Swift uses media to promote their star persona
At the beginning of her career, Taylor had the "cute girl next door image", partly due to her breakout hits: Love Story and You Belong With Me. This was definitely used when promoting her image:

2010 cover of a teen magazine

Even though she was 20 at the time the fact that she was still featured demonstrates the star persona she wanted to promote, a sweet and relatable girl, who has dealt with insecurities and sends quirky text messages with her friends. The font used for her name is a bright pink, a colour that is often associated with girls, which along with the cover lines "Move away from that boy!" and "Flirt with fashion" shows the superficial aspect of the magazine.

“When I need to vent or have a rant about something that’s bothering me, I’ll call my friends Emma (Stone) or Selena (Gomez), who can always cheer me up” she’s like a ray of sunshine! And Katy (Perry) always sends me the most hilarious text messages.”

On her fans: “They’re girls my age who I’d be hanging out with if I was at school right now. We have a close relationship. If they come to a few shows, I remember them. I’m not going to put up a weird barrier between me and my fans” I wouldn’t have any of this without them.”

This contrasts with the type of magazine covers she does now, as she's 28 and she's gone through a change of image with the release of Reputation. The colours used are much more darker, and for example, the dark red and bright orange fonts simply show that.
An aspect that still hasn't changed is the use of media to reach her fans, perhaps with a developed commercial side, with the "72 pages containing handwritten lyrics by Taylor" and "personal photos" along with "poetry and paintings". This is an example of how artists release their own products to promote their music while making fans feel special by collecting special limited editions.
She starred in the 2010's film Valentine's Day, which featured several other famous stars such as Julia Roberts and Anne Hathaway. The genre of the film, a light-hearted romcom, fitted with the expectations of her as a person in her early days. This appearance was during her Fearless and Speak Now era, hence why it was furtherly contributing to the sweet innocent image of hers. She also did the voiceover of Audrey in the animation film of Lorax, which additionally adds to her initial innocent image.  

Her use of social media had stopped after her incident with Kanye West, making her comeback really hyped and anticipated. She took to Instagram to promote her first single of the new album after taking a long hiatus.
Given Reputation is her second world tour, she's constantly promoting her tour on Instagram, with pictures of every concert in different cities, used in order to make the audience feel considered and also to promote future tours.
Her use of Twitter is more promotion rather than building her star persona and sharing her life, which is displayed by how her last tweets were months ago about the new video for Delicate and her opening acts for the upcoming tour; her retweets usually revolve around her, like when she retweeted Variety and Rolling Stone's tweets about the start of her Reputation Tour, and quoted "Amazing!" on James Bay's cover of one of her songs on BBC Radio 1's Live Lounge.

On late 2017 she released her first app, called "The Swift Life", which promises users they can interact with Taylor, "including exclusive pics, video, news and an experience you won't get anywhere else". This contributes to her brand and star persona which relies on her strong fan base and their wish to interact with her.

Lastly, recent news about her support for the democrats break her silence on politics of the past, showing a change of views, as she's now vocal about her opinions.

“In the past I’ve been reluctant to publicly voice my political opinions, but due to several events in my life and in the world in the past two years, I feel very differently about that now.”

 She goes on to argue against Marsha Blackburn, who hasn't supported equality for women and LGBTQ+, as she urges people to "please educate yourself on the candidates running in your state and vote based on who most closely represents your values." Some of her fan base are young adults, and this shows she's aware of it, because she's trying to encourage young people to vote. This contrasts with her silence on the last US presidential election, when unlike other artists she wasn't vocal about who she was voting for.