Come up with two characters. They need should opposites like a cheerleader and a nerd. Or a long-haired rocker and a mousey librarian. Now put them together and made them best friends or dating each other. How does it happen? How did they meet? Edward Cullen feel in love with accident prone Bella Swan and Katniss fell in love with someone who was very opposite from her. I don’t want to give it away if you haven’t read all three books.
But people who are very different from each other often end up together especially after being put into certain situations. Give it a try and have some fun.