Writing romance shouldn't be as discouraged as it seems to be. It's a fundamental part of human interaction, and if it has a definite impact on a story, then it can and should be written.
Chemistry describes how two people interact around each other. Bad chemistry is when two people are either too dissimilar or too similar, and their interactions are possibly "jagged" or businesslike. Good chemistry is when two people have traits that balance each other out, with some overlap, and their interactions are fluid, casual, understanding. If they were to be on a team, they would show excellent coordination. In fact, a team activity of any sort is a great way to show chemistry between two characters.
Basically, while physical attraction is the spark that starts the fire, chemistry is what makes and keeps that fire raging.
edited 28th May '11 12:46:36 PM by Five_X