Could you perhaps post a small sample here? It’s hard to give specific advice without a sample. It doesn’t have to be much.
When I go back to my shop tomorrow I will post an opening paragraph to a chapter. I struggled with it all day today and accomplished nothing. There is an evident weakness in my writing that I feel I can overcome or work through. I am very weak on opening statements, they are not compelling and thought provoking enough.
Looking forward to seeing your chapter.
Looking back, I’m guessing this is non-fiction. My wife has published about a dozen books for junior high level kids. (Real publishers, like Scholastic.) Word has a reading level tool. Run it on your chapter if you are worried that it is too simple, but the major things for you to think about are vocabulary and complexity of sentence structure.