Once one of the richest and most powerful cities in ancient Greece, nowadays Miletus is an interesting archaeological site, but not an unmissable one.
My suggestion
If you want to visit Miletus I strongly recommend that you go to the museum at the site's entrance first, as it will give you a good introduction to the site.
On the Aegean coast in Turkey, between Selçuk and Kusadasi, is found one of the principal ancient sites of Asia Minor: that of Ephesus, which still has many ancient Greek and Roman remains today. Unfortunately, of the previously grand wonder of the world, you will only be able to admire a few fragments of columns...
A cosmopolitan district of Istanbul, Kadiköy is one of the most lively areas of the mega-city. An authentic atmosphere blending modern impulses with its young population thrilling the old warriors looking to merge into the crowds.
Hasankeyf is in south-eastern Turkey, a very small city containing numerous natural and human wonders. Associated with a rich, ancient history, the diverse geological and archaeological particularities definitely make this village a place to visit. You must visit Hasankeyf as quickly as possible, because a dam project will soon completely cover this little gem.
Classed under World Heritage by Unesco for its numerous Ottoman houses, Safranbolu has conserved the charm of its old cities. Famous for its saffron, it is pleasant to wander its paved streets, to admire its aqueduct or to go and explore the caves of Bulak, nearby.