What to see
We would recommend to start exploring Istanbul in the Sultanahmet area with its obligatory twin attractions of the Blue Mosque and Hagia Sophia. From Sultanahmet you can walk to the Topkapi palace, the old palace of the Ottoman Sultans. From its gardens you can admire the magnificent view of the Marmara Sea. Of course when in Sultanahmet, you must not miss the Bazilica Cistern, the old byzantine water reservoir - if you are fan of photography you can take plenty of magical pictures here.
The Grand Bazaar is within easy walking distance of Sultanahmet. Here you can spend hours and hours walking in its streets and shops. And don't forget the golden rule - you are expected to bargain! It may not come as second nature to most Brits but we would recommend starting very low and then working your way up to a price that you are happy with. Remember you can always walk away... there are many other stalls around the next corner!
Another splendid view in Istanbul is the Galata Bridge over the Golden Horn - fringed with fishermen on the top and plenty of fish restaurants on the first floor. Cross Galata Bridge you will get to the new city, with Istiklal Street and Taksim Square - the main centre for night life. Every Friday and Saturday night the local pubs will get full with people of all ages. During the day Taksim Square and Istiklal Street are the places to do your shopping, meet people and relax in some of the many restaurants.
Another nice place for shopping is Besiktas with the nearby Dolmabahce palace - another palace from the Ottoman Sultans.
An absolute must in Istanbul is a Bosphorus tour. There are different companies organizing different tours lasting anything from two hours to a full day trip to the Black Sea. If you staying longer in Istanbul we would recommend a day tour to the Asian side which will give you a taste of the best sights and areas such as Kadikoy, Uskudar and Camlica Hill. Alternatively you can take a day trip to the fabulous Adalar, sip tea in Pierre Lotti's café in Eyup or take boat up the Black Sea to Anadolu Kavagi.