What to wear?

Contemporary clothing is widely accepted and there’re no rules or restrictions whatsoever; however, in order to avoid unwanted attention on public transportation or places of religious worship, it is best to dress modestly. If you’re traveling to different regions of Turkey it’d be very helpful to simply ask a Turkish friend about local customs including dressing.
If you're visiting a mosque, make sure to cover it up. That means woman have to cover their head, shoulders and knees. Men can skip covering up their heads.