I think most Turkish girls have straight and/or wavy hair. And I don't think there is a favoured hair colour or type. In general, when you have full, strong and shiny hair, people will like it. Wether the colour is blond, brown, black or the structure is curly or straight. But I must say that if you have blond hair, you'll get more attention since that's not a very common hair colour in Turkey (not rare, but just not that common).