The writing style of What I Saw and How I Lied is reflective of the narrator, who is a teenage girl. Because of this, the writing style is simple, confessional, and includes a great deal of emotional descriptions. For example, when Evie thinks of Peter, her thoughts almost read like a diary entry:
It sounded like the most romantic thing anyone could say. As if we were falling in love, and we knew it was wrong, but we'd do it anyway. We'd follow our foolish hearts. We'd listen to the crazymoon. (15.45)
Ultimately, the writing style is easy to read and follow, and flows in chronological order. We get all the events of the novel as they happen, and even though there are plot twists and turns, the writing style itself remains stable. Though not a diary, this book could totally work as one.