Most visitors stay on the European side of Istanbul and if they have limited time they take short day trips across to Uskudar or Kadikoy, which is located on the Asian side.
If you board your ship on Eminonu, voyage takes roughly 6 hours. It gives you an amazing view of the Hagia Sophia, the Topkapi Palace and the Blue Mosque. All along the Bosporus River, on the left and right, you can enjoy the view of grand villas and marble palaces added a modern twist to the stone fortress and small fishing villages nearby. You pass under the Bosphorus Bridge and come upon the Rumeli Hisari, also known as the Fortress of Europe. In about an hour and a half, your ship docks at Anadolu Kavagi. If you like you can climb up the hill where the Yoros castle located and reward with a panoramic view of where the Bosporus River meets the Black Sea.
When your cruise backs and docks to Eminonu you can walk towards the fish boats on the dock and have very fresh and reasonable fish sandwiches.