Give each part of the city its time.
Istanbul is spread across two continents and more neighbourhoods than you can reasonably visit in one short trip. A well-chosen day usually beats a long list of places that requires constant transfers.
Old City days
Build your historical sightseeing around Sultanahmet and nearby districts. Major monuments may have changing opening arrangements, separate ticket policies and queues. Check these details for your actual date.
Crossing the Bosphorus
Ferries are part of the city experience in their own right. A neighbourhood walk on the Asian shore or along the European waterfront can make for a very different day from the historical peninsula.
Traffic and travel time
Road traffic can be unpredictable. Ferries, trams, metros and walking may be more practical than moving by car between every stop. A private tour does not mean spending half your day in transfers.
Mosques and places of worship
Dress requirements and visitor access can differ between sites, and worship times affect entry. Your guide can help plan around the current arrangements.
Layovers: be conservative
IST and SAW are separate airports. Leave ample time for border formalities, baggage, city transfers and security. An itinerary should never depend on optimistic traffic estimates.
When you're travelling with children
Choose fewer stops, plan pauses and avoid squeezing a full historical programme into the hottest part of the day. Tell the team about pushchairs and mobility needs when asking for a route.