You will need to take...
Passport; Non EU country,
Sun glasses; it's very bright,
Sunscreen; it's very sunny,
Soled shoes; for walking off road,
Turkish Lira; most places take £ pounds, but a few YTL is a good idea,
Debit card; Chip and PIN, is the easiest way to pay at Supermarkets, Eating out and Garages
Toiletries; just what you would use at home,
Drivers Licence; if you are hiring a vehicle,
Mobile phone; very few land lines outside of major towns, you need to confirm your return flight.
Swimming stuff; costume, snorkel, mask, flippers, in-water shoes for standing on rocks,
Hat; The sun is very hot when overhead,
Books to read; its your choice! But we recommend you take some,
Alarm clock: sleeping can come easily, and sleeping late easier, especially if you have a plane to catch,
Sandals, you're on holiday after all,
and whatever else you personally want.