5 Tips on Discovering Istanbul
(1) People. Friendly! The most you will have to worry about is that you need to find a WC because of all the apple tea you just had. (2) Tours. Forget it, especially the hop on hop off buses (too much traffic). Get lost in the culture and discover it all by walking. (3) Where to stay. Stay in Old Town if you want to be close to the major attractions and traditional shopping. Stay in Taksim if you want nightlife and modern shopping (brand names).
Insider Tip:(4) Attractions. Haghia Sophia is closed on Mondays. Topkapi Palace is closed on Tuesdays. And The Blue Mosque has certain hours due to prayer times. For The Blue Mosque, don't worry about the dress code. They will give you a cloak to cover your bare shoulders, shorts, and hair. (5) Food. EAT IT ALL whether it's lokum, baklava, eggplant and lamb kebabs, stuffed mussels (my personal favorite), etc. There is a food tour from My Local Guide Istanbul called "The taste of two continents". DO IT!