Begin with the icons, but resist treating them like a checklist. In Sultanahmet, Hagia Sophia, the Blue Mosque and Topkapı Palace sit within easy reach of one another, each with enough presence to slow the day down. Galata Tower offers the classic rooftop perspective, while Dolmabahçe Palace brings the Bosphorus into the picture.
Then change pace.
Karaköy is made for wandering, Bebek for a waterside pause, and Arnavutköy for an unhurried afternoon.
Then there is Tersane Istanbul, the newer addition on the Golden Horn. Restored historic buildings, open air spaces, restaurants and waterfront views make it feel closer to a day out than a conventional shopping stop. Go for the art, stay for lunch, and accept that the shopping bags may multiply along the way.
The best route is rarely the most efficient one; in Istanbul, a detour usually improves the plan... So clear your calendar — this city's autumn art, music and theatre scene is too good to miss.