This might sound surprising because emotion/tone/mood is such a big factor of stories, but as I was peer editing a lot of stories, I realized how monotone and emotionless people write their characters, especially since it seems like they're trying to express something much deeper within that they can't get across. Get someone else to read your story objectively, and ask them if they felt anything. In the end, people like to read stories because of the small aspect of relativity that they feel, that escape where they can imagine their lives are just as cool or romantic as their favourite character's, so it's really important to trigger raw and deep emotion within people.
