Buy as many American history related books as possible focusing on our founding, the reasons why, the civil war, the reasons why, and then mathematics, because numbers do not lie, learn statistics and how they can be manipulated, so you know when and how information is manipulated and you are being lied to. Study your bible as often as you can. Physical strengthening and mental strengthening go hand in hand. As far as choosing classes? Pray and let God guide you choices.