Taxis are easy and relatively cheap—a ride from Sultanahmet to Taksim is usually less than $5. Many drivers don't speak English, so write your destination on a piece of paper. Ask your hotel to call a taxi or find a stand in front of a hotel—you'll be more likely to get a driver who won't take you the long way around or use the more expensive night rate (make sure the meter says "gündüz" before midnight, meaning the day rate).