Disciplined people don't have more willpower than the average person. They just spend most of their time in environments where good behavior is encouraged and where bad behavior is either invisible or discouraged.
Do you want to become more disciplined? Create a more disciplined environment:
Those who seem to have the most willpower are those who need it the least. Look around. Do you see something that's tempting you into bad behavior? Something that you continuously need to resist?
Put it away. Block it. Make it invisible. Clean up your environments this way and you'll become a more disciplined person.