Another tip which I can give from my own experience is, learn all those parking signs and stuff. There are no english boards to help you there. Some streets allow you to park only during specific times in a day, and some you have to show that parking indicator in your dashboard before you leave the car, and in some places you have to pay. Yes I got one ticket for wrong parking once.
You should be also clear about what you are supposed to do when you are behind the wheel and you happen to hear a loud siren from behind - Ambulance / fire truck.
Even though Autobahn has no speed limits in most of the easy stretches, they do have dynamic speed limits in certain areas and static ones in curves and all. Follow the traffic - do not overspeed or slow down too much - in these places and you will be fine.
Even if Polizei stop you while driving, do not just get out of the car to explain anything. Wait for them to come to you - guess you already know this.
Apart form your passport and DL, its always better to carry your ID card if you work for some well known firm - like Siemens. Once, when stopped by the cops, they started behaving very friendly and one of them even started joking about Siemens's mustache (his hologram'ed face in the id card) once I produced it togther with the passport.
