Juliette is a main character. She has a special power that she has to deal with in this dystopian world. Adam is also important. He has a connection with Juliette and they go through a lot together. Warner is another key character. He's complex, being both a villain and someone with his own motives and desires.
Well, in 'Shatter Me' dystopian novels, there's a sense of isolation for the main character. Juliette is isolated because of her power which she can't fully control. The novels also have a lot of action - there are battles and struggles against the oppressors. And the way the future is envisioned, with limited resources and a lot of fear among the people, is a typical feature of dystopian novels.
In these novels, Warner is a very important character. He has his own motives and his character arc is quite complex. Kenji is also a main character, often providing support and comic relief in the story.
One of the main themes is self - discovery. The protagonist often has to face her own identity and powers, which she doesn't fully understand at first. Another theme could be love and relationships. There are complex relationships that develop between the characters that play a crucial role in the story.
One idea could be exploring a different backstory for Juliette. Maybe she had a secret friendship before being locked up that influenced her powers in ways not shown in the original. Another is a what - if scenario where Warner wasn't as antagonistic from the start. He could have been forced into his actions by some external power.