How do I inculcate honesty in my three-year-old from now only?

Parents are the first teachers of their children. So, to inculcate honesty in your child you need to practice it first. Never make any false promises to the child else he will learn the same. Encourage him to speak truth always, support honesty always. You can tell him short stories, both fictional and about real-life people, who believed in honesty. Tell him that if he makes any mistake he should come and tell you instead of hiding it. If he does that instead of scolding him for his fault appreciate the fact that he could be honest. Instead of giving lectures simply keep it short and simple so that he understands things better. http://www.kidsworldfun.com/blog/inculcating-values-in-kid/