To get more bonuses, do the following. After you complete the game, watch all credits and thus you will receive 200 points. If you go under the chap menu and watch the credits again, you will get plus 200 points, in this case. Actually, you can repeat this trick for unlimited bunus points!
Sometimes, when you have to answer a question, your character don't have enough mental health. So, try to give the wrong answer. Even if you do this intentionally a few times, you can succeed.