Hi Khalida,
I know Istanbul very well as my husband is from there and we go very often.
I have a full written memo at my office which I can post on Monday with all sort of tips.
For a short overview in a nutshell:
Worth visiting old city:
Eminonu (neighbourhood), Kapaliçarsi (Grand Bazar), Egyptian Bazar. If you want to buy rhinestones, sequinces, fringes, swarovski, beads, fabrics, byoux, etc. then shop in Eminuno, you will find loads in littles shops and wholesale stores in the little streets behind the Egyptian Bazar. If you want to buy gold and silver; buy in the Grand Bazar.
Sultan Ahmet (neighbourhood) visit: Top Kapi, Aya Sofya, Blue Mosque, Cistern. Food in old city is mostly for tourists but in Kumpapi downhill Sultan Ahmet you will find many restaurants which are touristic too but the atmosphere is very nice.
Most quality dinnerclubs to see dancers:
Kervanseray in Taksim.
Orient House: in the old city near top kapi and grand bazar.
then you have dancers at Sultana, Galatower and Kiz Kulesi night show.
I saw the best dancers at Kervansaray and Orient House.
You can try to get a workshop from Sema Yildiz
SEMA YILDIZ BELLYDANCE TEACHER. She trained up Didem and many other famous Turkish dancers.
Modern City:
Taxim, Beyoglu (Istiklal Caddesi = main street with all sort of shops)
Sisli, Rumeli Caddesi (expensive stores you will find at Rumeli Caddesi)
Lovely neighbourhouds with lots of shopping and fishmarkets near bosporus:
Besiktas, Ortakoy, bebek (lovely restaurants with Turkish singers in Bebek and Tarabiya area), Tarabiya, Istinye, Rumeli, Sariyer (great fishrestaurants here as well).
Must see Shopping Centres:
Ak Merkez, Kanyon, Cehazir (is near Bella so maybe you can combine), Istiyne Park Shopping Centre (this is opened I think last year it is MAYOR)
I will post some other restaurants with no dancers but famous for food on Monday.
Must go Clubing restaurant: REINA
www.reina.com.tr located in Ortakoy. Ortakoy and Taxim are good places for clubbing.
Nowadays you can travel by metro from modern city to old city, it is much more comfortable than by bus. You can take a taxi but they often rip you off, you can't agree a price because they work with taximetre and If you don't know the city they drive you in circles for about an hour.
Ok more on Monday. Have fun preparing!
Amira