Good advice so far (as usual).
Now, to open a can of worms: SE or CE? I hear both being recommended.
In favour of the CE is a lot of grassland (underneath that jungle) that lends itself to cottaging.
In favour of the SE is a lot of grassland (underneath that jungle) that lends itself to farms.
Since I've mostly improved tiles with farms around Istanbul, I might be well on my way to a SE. Certainly I haven't played a ALC with a SE for some time (Frederick, and sort-of with Alexander). SE certainly offers early-game tech advantages, whereas the CE takes a lot longer to get going.
On the other hand, as I recall, the SE relies upon war booty for gold and popping GP to trade techs. I see problems here already. Let's assume the worst (always a good idea): we're isolated from contact until Optics, and from military until Astronomy. That rules out warring and tech trading for a long time. Also remember that although Mehmed can run larger cities earlier than other civs, he's not Philosophical.
At this point I'm leaning towards the CE, and the deciding factor is my familiarity and comfort with it as opposed to the SE. With all the other challenges this isolated start is presenting, I think I could do without an economic model I barely know how to implement and manage, especially not, in these circumstances, optimally.
However, as always, I am open to convincing arguments.