First, you should do some research on both universes. Know the characters, the rules, and the settings of 'Worm' and 'Fate'. For example, understand how powers work in 'Worm' and the mechanics of the Grail War in 'Fate'.
Next, come up with a central plot idea. It could be something like a crossover of a specific character from 'Worm' into the 'Fate' world and their journey there. You can start with a simple concept, like Taylor from 'Worm' accidentally being summoned as a Servant in the 'Fate' universe. Then build on that, thinking about how she would interact with the other Servants and Masters.
Chapter 311, "Signed Jiang Yan", is the clearest early answer because it turns Shen Lan's situation into a concrete plot event. It opens with Shen Lan knocked on the door before entering when Jiang Li was... and closes on His acting skills are quite good, as everyone can see, and most....
Chapter 695, "Is This a Matter of Money?!", is the clearest early answer because it turns Shu Yue's situation into a concrete plot event. The chapter gives readers a real answer by opening on Shang Shuyue just felt she was out of luck.
Chapter 733, "Those People from the Jiang Family Are More Stupid than the Next!", is the clearest early answer because it turns Xu Ning's situation into a concrete plot event. The chapter turns that into something concrete by moving from Okay, Sister, you should go to sleep now.
Chapter 690, "Miss Jiang, Marry Me!", is the clearest early answer because it turns Wen Jiaojiao's situation into a concrete plot event. The chapter gives readers a real answer by opening on No wonder she had predicted she would come into some unexpected...
Chapter 883, "Give Her Two Slaps and Make Her Go Far Away!", is the clearest early answer because it turns Slaps's situation into a concrete plot event. It opens with I'm worried about you, aren't you two like water and fire?" "Not...
Chapter 617, "Moral Kidnapping? No Such Thing!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from The cabin wasn't far from the lake, just around fifty meters away.
Chapter 848, "Just an Adopted Daughter", is the clearest early answer because it turns Yet Gu Qiang's situation into a concrete plot event.
Chapter 705, "Is She Her Own Destined Noble Person?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 904, "Welcome Young Master and Young Madam!", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event. The chapter gives readers a real answer by opening on Jiang Bufan and Jiang Buchen immediately ran up in surprise.
Chapter 434, "The Identity of the Feng Shui Master Can't Be Hidden Anymore", is the clearest early answer because the hidden truth stops feeling like mere subtext. The chapter gives readers a real answer by opening on He thought Jiang Li was just talking, but to his surprise, there...