Much of Turkish entertaining occurs in restaurants. Should you be invited to dinner in Turkey, do not offer to split the bill. The host always pays - by this same token, if you invite others to dinner at a restaurant, make sure you are prepared to pay for everyone.
It will be rather rare to receive a home invitation for lunch or dinner in Turkey. However, if you have the good fortune to be invited, accept. Like in Germany, bring flowers, but never bring wine or any other alcoholic beverage. Turkey is, after all, a Muslim country and you can make a big mistake there. You may bring chocolates instead.
When arriving, take off your shoes, even if your host tells you that it's not necessary. You will find an array of slippers waiting by the door.
Food in Turkey, particularly chicken, is more often eaten with your fingers than with cutlery. Lemon cologne will be splashed over your hands before the meal starts and again afterward. Unlike in Germany, expect there to be smoking breaks between courses.
For religious reasons, lift only your right hand to your mouth. Your hostess will say: Afiyet Olson, which means: enjoy your meal and you reply the same. Make sure that the eldest diner is served before you and, although Turkish meals are a lively affair, never speak with food in your mouth.
Unlike in Germany, asking for a second helping is a compliment, so go ahead. When using cutlery, the continental way applies, that is to say, fork in your left hand and knife in your right. Compliment the food and, if offered, accept a Turkish coffee to round off the meal. When drinking Turkish coffee, make sure you leave the coffee at the bottom and do not gulp. You'll find coffee grounds in the bottom of the cup, and this drink is meant to be savored.