How do I know when a verb takes haben or sein?

The easiest way to think about these verbs when forming the present perfect is to think about what they do. Haben is the verb we use most regularly, and if you are in doubt, it's usually the one to go for. For working out if a verb takes sein, you can usually tell if the verb is describing movement - that's fahren or gehen. Or if it's a change of state. That just means if the verb is describing a difference or change in situation, like aufwachsen - to grow up - for example.