How do I decide if I am doing the right thing?
By what standard do you personally make moral decisions? For example, many people adhere to a particular religion and use it as their moral compass. Others simply do what feels right at the moment.
What about you?
How do I trust anyone?
What do you believe about people? Are the generally good or generally bad?
Do you consider yourself trustworthy? Why or why not? What do you believe is the risk if you trust others? What is the risk if you chose not to trust others?
How do I predict human behavior?
Why do you want to predict human behavior? What is the outcome you are looking for? Can you predict your own behavior? What would change in your life if you could predict the behavior of those around you?