If you are writing in first person you might fall into the trap of using too many I statements. While it's perfectly natural to use I in first person writing, don't fall victim to passive voice from overuse!
I see Jacob walk into the room.
Well, duh. Of course you see it! You're the narrator.
Jacob walks into the room.
Much more active!
A few more examples:
"I'm not sure."
I sense her hesitation.
She hesitates, "I'm not sure."
It's perfectly okay to filter description through your narrator but keep it balanced. If you filter everything through her lens, it robs other character's action and creates a voice that sounds more passive.
To check your use of I statements, print a few pages from your manuscript and circle every I. Go back. Do you need every use of I? Try to balance it out by filtering important actions through your first person narrator and use active subject-verb structures.
How would you change this?
I saw Annabelle enter the room. I thought she looked pale and frightened.