Keep your dialogue authentic. According to David Niall Wilson, dialogue can't be the place to shovel in background information about other characters in the story. If the narrator is talking to his best friend, the friend won't be using that conversation to tell the narrator what he does for a living, or where he lives. Those are facts that the narrator would already know, making that conversation unnatural.
Reveal the personality, or "voice" of your narrator through diction and reaction to events. Give the narrator some time to ruminate out loud for the reader (but not to the point of boredom). Readers will gravitate toward a narrator they sympathizes with, and if you can get the readers on your side, your novel will flourish. Leif Enger's "Peace Like a River," for example, has a first-person narrator whose father miraculously brings him back to life after his doctor had pronounced him dead at birth, and whose brother runs from the law after an accidental murder. The reader's sympathy with the boy leads him to share the boy's wonder at his father's miracles and his brother's courage.
Use all the tricks of rewording at your disposal to keep the word "I" from dominating your novel. Otherwise, your text will look like it has tiny black worms throughout it, and it will read like an kid's picture book. Instead of using constructions like "I was afraid when the werewolf howled," you can say things like "My body trembled with each echo of the wolf" or "The constant howling started to fray all of my nerves."