The best way to visit Istanbul and all around Turkey is to hire a private tour guide. Hagia Sophia, Blue Mosque, Topkapi Palace, Basilica Cistern, Bosphorus, Chora Museum, Museum of Archeology in Istanbul are the main attractions. You can get the best from your visits to the places places below with a certified tour guide.
Antalya : Antique cities of Perge (Pergea) and Side, Aspendos Theatre. Waterfalls and the turquois beaches.
Cappadocia Ihlara Valley, Goreme Open Air Museum, Derinkuyu Underground City. The places where you would definitely benefit from a private or local tour guide.
Canakkale : The archeological site of Troy and the memorials in Gallipoli Peninsula.
Izmir : Ancient Ephesus, old Greek cities like Miletus, Didyma and Priene.