Being 'good' means you have a good working moral compass that you choose to follow. Good people are defined by their actions. Actions could include things like:
1) When you find yourself putting other people first
2) When people say they can trust you
3) When you feel compelled to "do the right thing"
4) When you have compassion for others
5) When you make decisions you know you will have no regrets about
Usually you can trust your own judgement by the feelings in your heart.