What factors contribute to Scout's character traits in To Kill a Mockingbird?

While Scout is very much her own person, her family and community play large roles in shaping her character.
Within the Finch family, the most important factor is that her mother is dead. Her father, though attentive, works a lot, and Scout becomes a tomboy, palling around with her brother. This situation changes as her aunt moves in to provide some feminine guidance.
The other vital family factor is her father's integrity and intelligence. He is innately fair-minded and aims to be just in his work and daily actions. He takes Scout's thoughts and questions seriously.
Life in their Southern town also affects Scout's character. The everyday class struggles during the Depression in a small town, especially the institutionalized racism of the segregated South, start to weigh heavily on her as she grows up. Being Atticus's daughter and therefore being around Tom Robinson's trial puts her in danger and makes her aware of existing social and racial schisms. As she gains awareness and maturity, we see how her character has been affected by her father's example.