One memorable moment is when Ginny first stands up to Draco Malfoy in defense of Harry. This shows her loyalty and courage, and could be the start of a fanfic where Ginny continues to be a fierce defender of Harry in different situations. Another moment is when Ginny kisses Harry during the Gryffindor victory celebration. A fanfic could explore their relationship development from that point on.
The moment when Ginny finally tells Harry how she really feels about him is quite significant. A fanfic could be written about how Harry processes his feelings in response to Ginny's confession. Also, their time together on the Quidditch pitch, especially when Ginny plays really well and Harry admires her skills. This could inspire a fanfic about their shared love for Quidditch and how it brings them closer.