Shido Itsuka
Due to her past, when Miku first met Shido, she has great dislike towards men, seeing all of them as depraved and perverted who only hypocritically liked her and sees Shido as no different and would attack Shido on sight. Because of this, Shido was forced to crossdress as a girl (renaming himself as Shiori) to get closer to her which piqued Miku's interest.
However, upon finding out that that "Shiori" is actually a guy, Miku was extremely angry towards this and her hatred towards Shido worsened. Eventually, when confronted by Kurumi and Shido, Miku remained stubborn and could not believe Shido truly cares about Tohka and she even mockingly offered Shido a harem of girls with her powers if Shido admits that he was just pretending to be a hero.
Miku's attitude towards Shido (and men later on) soon changed when Shido revealed her past and even defended Miku from Inverse Tohka's attacks, and Shido's promise to protect her and be her fan no matter any circumstances ultimately fell in love to him and allowed him to seal her.
After being sealed, Miku clings to Shido at every opportunity and calls him "darling" affectionately and would often try to flirt with Shido even at public places. Although Shido reciprocates the feelings, he nonetheless noticed that Miku has been behaving a little bit childish when they interact. Miku also actively tries to make Shido crossdress as Shiori as well much to the latter's disapproval.
Tohka Yatogami
After being sealed, while taking a liking to all the Spirits, Miku took a particular liking towards Tohka, taking every opportunity she can to hug her, much to Tohka's annoyance and embarrassment.
Rindouji All-Girls Private School
In her pre-sealed state, Miku didn't care about her schoolmates and simply used her Solo to take control of them and rule the school. Even if someone would get in her way, she would simply increase the strength of her Solo to get her/them back under her control. She would invite girls she had taken a liking to over to her house and drink tea together, but if Miku finds another girl that is more interesting than the girl she invited, she would quickly dump her and take the other girl to drink tea with her without even thinking of how the girl she invited first might feel.
Her current relationship with her schoolmates after having her spirit mana sealed is unknown.