If you an author going through the editing process, you've probably been cited for filtering. I know I have. So what is filtering? Basically, it's being an intrusive narrator. For example, instead of writing: He heard a bird chirp overhead. Just write: A blue jay chirped overhead.
The reader does not need to be reminded that someone is telling a story. He or she needs to experience it through the character.
Theses are some filter words to avoid:
to be able to
to sound like
Instead of: I watch the wave crash on the shore.
The wave crashed on the shore.
Filter words or phrases are added at the beginning of a sentence to the world as filtered through the character's eyes. Instead, the reader experience the scene without a filter. It is more realistic that way.