Humans are said to have values and instincts. So humans must have some good character traits. To be a good person, you need to have some characteristic qualities. For example -
Being honest - A good person must have honest qualities. He will never adopt dishonest ways
Truthfulness- A good person must always try to speak the truth. He will never resort to lies.
Being altruistic - A good person must be altruistic. He will always try to help others.