Christians are those who love God and Jesus Christ. They strive to be like them. When you strive to be like Jesus, you become a better person because he is the best person.
Being like them doesnt mean you need to be perfect immediately, and when you mess up, its over. It means you become kinder, more truthful, more honest, more believing everyday until, eventually, you become like him.
But we never could become like Jesus without the Atonement, because we all make mistakes. Through his love and sacrifice, we can become clean!
Through small and simple things, great things are brought to pass.