Entering a restaurant
It's still customary for a man to enter the restaurant first - in the old days, this was to check out any danger!
Table service
The waiter is always addressed: 'Herr Ober!', but beware of calling the waitress: 'Fräulein!'. Expect the waiter to be correct and formal.
Paying
The price should include waiter service, but if you wish to give a tip, say a further 10%, just say: 'Ist gut so' or 'Stimmt so' when you pay. If you don't have enough change to do this, just state the price you wish to pay, eg: 'fünfundsiebzig, bitte.'
The waiter may ask: 'Zusammen?', because this makes his life easier! If you wish to have separate bills, say: 'Getrennt, bitte.'
Saying 'you'
'Sie' is for formal address.
'Du' (old English 'thou') is the familiar form, used when talking to children and animals, and with those closest to you: for example friends and colleagues.
If unsure, wait till you are invited to use the 'Du' form. Notice how Andreas stumbles a little when he first starts to use this form - he is indicating that he doesn't take this new privilege too much for granted!