Language:
Turkish is the official language, but English is widely understood in the main tourist areas.
Communications:
The international country dialling code for Turkey is +90. The outgoing code is 00, followed by the relevant country code (e.g. 0044 for the United Kingdom). City/area codes are in use, e.g. Istanbul Asya (Asia side) is (0)216 and Istanbul Avrupa (Europe side) is (0)212. GSM 900 and 1800 networks cover most of the country. Internet cafes are available in the main towns and resorts.
Stay healthy:
Tap may not be safe depending on where you drink it. Although the tap water itself is clean, many local water tanks are not maintained properly, and one should try to avoid tap water if possible. Locals widely prefer bottled water and the same applies for the restaurants.
Food and drinks are mostly of international standards. Some Turkish foods are known to use a variety of spices which may affect international tourists who may not be accustomed to such ingredients, although most of it is edible for any tongue.
Use common sense when buying certain foods, particularly from street vendors. Delicacies such as "Firin Sutlac" (a kind of rice pudding) can go bad rapidly on a hot day, as can the oysters occasionally for sale on the streets.
Stay safe:
As with most European cities, but especially in crowded areas of Istanbul, watch your pockets and travel documents as pickpockets have devised all sorts of strategies to obtain them from you. Do not rely too much on the 'safe' feeling you get from the omnipresence of policemen.
Istanbul is home to three of the biggest clubs in Turkey and arguably European football: Besiktas, Fenerbahçe, and Galatasaray. It is advisable not to wear colours associating yourself with any of the clubs black&white, blue&yellow, and red&yellow respectively, particularly on the days of matches between the sides due to the fearsome rivalry they share.