The Sugar Apple Fairy Tale manga has indeed finished. It provided a satisfying conclusion to the tale. The final chapters tied up loose ends and gave a proper ending to the characters' journeys.
One idea could be to explore a side character's backstory. For example, you could write about the early life of a minor fairy in the Sugar Apple Fairy Tale world. What made her the way she is? What dreams did she have before she got involved in the main story's events? Another idea is to create an alternate ending. Maybe in your fanfic, the main characters make different choices that lead to a completely different outcome for the fairy tale world. It could be a darker ending where the magic is lost, or a happier one where more characters find true love.
Sure. One popular 'Sugar Apple Fairy' light novel might be the original series itself. It often has an engaging plot with unique characters. You can usually find it in local bookstores or online platforms dedicated to light novels.
I'm not sure about specific reviews offhand. But generally, it's praised for its unique fantasy world setting and engaging characters. The story's blend of magic and the journey of the protagonist is often lauded.
Create a complex plot. Don't just rely on the simple plotlines from the original. Add twists and turns. Maybe introduce a new prophecy that the characters have to deal with, or a hidden power that one of the characters discovers. Incorporate different themes into your fanfic. If the original was mainly about love, add themes of friendship, sacrifice, or self - discovery. And don't forget about the setting. Expand on the fairy tale world. Describe new locations, like a secret forest filled with magical creatures that no one has ever heard of in the original story.