Turkish driving tests are very basic and hence Turkish motorists are not the best trained, so be alert and drive defensively. Be wary of blind corners as cars will start to overtake before they can see the road ahead.
It is the law in Turkey to have photographic ID on you at all times. Your car will have it's own document
On motorways you should be fine but bare in mind that on local roads they sometimes don't put signs or cones up for road works and I have nearly had an accident at night where they put dark coloured stones out in the road as a warning.
Other than that the roads are normally fairly clear and it's a great way to see the country. As an alternative there are long distance buses which are cheap and reasonably comfy.