I'm a server in training, give me your tips!

No pun intended :D

Ok so I will be training as a server. What do you look for in restaurant service! What do you find to be the perfect balance of service? What is annoying?

Also, I have a birthmark under my eye. Can you help me come up with quick witty/jokingly loving responses when they ask, “Oh dear, what happened to your eye?”

I want to stick to like 3 lines. (Otherwise sometimes I get caught off guard and I lose my joke of thought.)

Thanks all.