Characters - they are what move the story along. They can come in millions of different unique personalities. They can be a spunky and fun blonde with blue eyes or a rebellious teen who doesn't like to listen to their parents. It can be anything your mind wants it to be, even if it is a cat or dog. Just remember to be original, creative, and have an open imagination. Personally, I find it easier and more fun to write fan fictions because their personality is already created. I also find it easier to write fan fictions since all the characters are the characters I have fallen in love with. To me, having likeable characters make me excited to keep writing.