Kadıköy is a bustling district on the Asian side of the city. There is a market and lots of small speciality shops, such as cheese, honey, herbal, gold, antiques and second hand books. This is the place to see the Istanbul of Istanbullus. After browsing for an hour or so sit down at one of the many small restaurants for some meze or fish. Try the "midye dolma", battered mussels. Çıya is a favourite restaurant of locals and visitors if you want to try unusual Turkish food. Keep an eye open for the fortune telling rabbits.
Take the ferry from Eminonu or Karakoy. Walk straight ahead, cross the road and dive into the side streets on your right.
Google map: bit.ly/n0pKUJ