As a Turkish person who lives in İstanbul i'll try my best at explaining. I'm sleepy right now so excuse my writing. -Other user u/janebirkin explained a lot but i disagree with what she says about clothing. Things with logos and texts is extremely common in here. And you can see a lot of people with Lakers and Chicago Bulls hoodies. This is not a hint of being American. -In Turkey most places you don't need to dress modestly, it's really depends of where are you going. Right now i assume you will follow classical tourist route. İstiklal Street, Sultanahmet(mosque and few other touristic spots), Grand Bazaar, some mosques... In Sultanahmet, Grand Bazaar and mosques you should dress modestly. If you want to enter the mosque you should cover your arms. More clothing=less need for coverage which is easy for you. And this places sellers is kinda creepy. They harass Turkish people, they probably harass you too. Besides them, there is so much Arab tourist and you definety get looks from them. -In İstiklal Street clothing isn't matter but you should look after your bag because pickpocket is very common. -Some people waiting front of venues like cafes or bars. Some of them probably intive you there very insistently. If you enter this places, you probably will be overcharged. And please instead of taxi, get an Uber. Taxis will harass and overcharge you. Even Turkish people don't use them anymore. -I don't know what type of travel you want want. But Galata Tower, Basilica Cistern, Maiden Tower and museums by your interest definetly should be in your travel list. -Besides that we don't have that much touristic spot and i don't know much about Anatolian side. But if you have time Baltalimanı Japanese Garden is really amazing. For eating you can go to Beşiktaş, Cihangir or Bağdat Street. Bağdat Street is more like a shopping street but it has a lot of good cafes too. If you are into clubbing Taksim is place to do that but i don't recommend it. You probably get so much unwanted attention and this will cause some trouble. More lowkey things like go into a bar is sounds a lot better. Kadıköy and Beşiktaş my go to places but this places have some much student. So nothing fancy but at least is it fun. I try to explain but i probably miss a lot of things. Feel free to ask me, i would like to help!