For a truly local experience, head over to the fish market located on the street opposite Galatasaray Lise about half way down Istiklal. Not a place for the indecisive as there are about 20 meyhanes with a variety of meze and drinks to choose from. Sit with the locals as they attempt to make you sample each and every spice, coffee, and teas. If the weather is unfriendly, head indoors and feel the exciting buzz of the noisy crowds in the Cicek Passaj (indoor food court). To bypass the "tourist" scene, avoid the Sultanahmet, as the prices are higher, there are hoards of camera wielding safarians, and you'll find better quality of food within the local circles.