Ensure the protagonists are well-defined individually so that their union feels like two whole people coming together rather than one completing the other. Popular Romantic Tropes for Inspiration
A relationship that builds subtly over a long period. whether it's physical
Incorporate flirting and nicknames to show comfort and playfulness between characters. whether it's physical
High school best friends reuniting and discovering hidden feelings. whether it's physical
Every great romance starts with an immediate draw, whether it's physical, intellectual, or based on a shared secret.
Two characters who start with mutual disdain but find common ground.