I'm currently writing a monster story and I've been trying to drag it out. For those of you who have read my previous stories, you know that they are short and no longer than 2,000 words, however this time I'm planing on making this one longer. I'm not sure how long but I'm aiming for at least 5,000. What I'm wondering though is, considering the fact that I'm doing a story on monsters, and it's a bit longer than normal: What are considered cliches in monster stories? and What should I do to keep my story from starting good and going down hill fast in quality? 

I don't mind if you ask questions about the story, but I will say that I might not be able to answer all the questions as I don't want to spoil the story too much.

Thank you!