Well, try to think of a fandom you love. Also write from your heart. Let's say you want a story about Harry Potter maybe think of your favorite or least favorite character and make up a character that relates to them. If maybe you want Doctor Who maybe the Doctor could have a sister or brother or he could get girlfriend. Also if you don't want to make up characters add in new story lines. I'm not really good at giving advice so.... Also if you have 2 young characters that will date when they get older do not make them date and kiss at like 10 years old. I hope this helped I guess
