You could check out fanfic platforms like Archive of Our Own. There are often some great 'Blue Bloods Daughter' fanfics there. Just search for the relevant tags.
Emotional depth is also important. The fanfic should make the reader feel something for the 'Blue Bloods Daughter'. Whether it's sympathy for her struggles, joy in her achievements, or excitement for her future. It should be able to draw the reader in and make them care about what happens to the character.
One idea could be a time - travel fanfic where Danny's daughter travels back in time and meets a younger version of Danny. This could lead to some interesting interactions as she gets to see a different side of her father and also has to navigate the past without changing the future too much.
There could be a fanfic that delves into the backstory of one of the Reagan family members, like Erin. It could tell the story of how she decided to pursue a career in law and the challenges she faced along the way. This would give more depth to her character in the Blue Bloods universe.
Some fanfics might give her a unique talent or interest. It could be something like painting, which she uses as an outlet for her emotions. This aspect of her character can add depth and make her more relatable to readers. Writers might also show how her family supports her in this pursuit, further highlighting the family values in the story.
One idea could be to focus on Frank's backstory before he became the Police Commissioner. Explore his early days in the police force, the challenges he faced, and the relationships he built. This can add depth to his character in the fanfic.
Good writing quality matters a great deal. This includes proper grammar, vivid descriptions, and a good flow. If the writing is choppy or full of errors, it's going to be hard for the reader to get immersed in the fanfic world of Blue Bloods.
The writing style and tone could make it distinct. If the author of 'blue bloods a perfect oc fanfic' has a more humorous or darker tone compared to other fanfic writers in the 'blue bloods' fandom. The way the story is told, whether it's through a series of flashbacks or a very linear narrative, can also set it apart from other fanfics. And perhaps the author has a different interpretation of the 'blue bloods' lore, which is reflected in how they develop the OC and the overall story.
To develop Frank's character, start by researching his personality traits shown in the show. Then, give him new challenges that force him to grow. For example, a political scandal that threatens his position can make him reevaluate his values.