I lived there for a couple of years, absolutely brilliant city! Vibrant, busy, steeped in incredible history whilst also being cosmopolitan. Truly an east-meets-west vibe.
Recommendations might be a bit dated though:
- The obvious ones are visiting Hagia Sophia, The Blue Mosque (both in Sultanahmet Square), Topkapi and Dolmabahce Palaces, Basilica Cistern. Although very touristy it's highly recommended just to take in the bustle and history of these structures and areas.
- Grand Bazaar (European side) and Bahariye Street (Asian) for gift shopping.
- Rumeli Hisari isn't quite as popular but its a great old fortress from medieval times that used to protect the Bosphorous strait on the now European side.
- I'd recommend Ortakoy on the European side, it's by the Bosphorous and in the evenings is really buzzy with roadside food offerings and local bars. Great place to chill, have a few drinks and take in the city vibe
- It's worth doing a Strait tour or dinner cruise if you have time. Really good way to see the city skyline and architecture on both sides
- Galata Tower gets very busy but the area around it is pretty cool including Istiklal Caddesi. Part of the Beyoglu area which has lots to check out and restaurants, bars etc
- Taksim Square can get VERY busy but always worth a little venture.
- The Asian side is the 'older' side but has loads of great places like Kadikoy (check out the murals) and it's bars, shopping and general buzz.
- Balat is the place to get your pic on the coloured steps and has an old Shoreditch-y vibe.
- I'd always prefer to get the ferry across the strait but if you want to tick it off then get a taxi across the bridge. On transport, when I lived in the city there was no metro, however I went back in 2019 and did most of my travelling on the system, really quick, easy to navigate.
Don't know what sort of budget or preference you have for hotels, Istanbul has some exceptional places to stay if you want to be spenny. Last time I stayed we found this cool little place near Galata Tower
http://www.bankerhan.com/home but I'm sure there's also some decent airbnb's if that's your thing.
On the football front, I can't help there. I don't know how easy it is to get tickets nowadays but if it's anything like it was, it's truly an experience so worth persevering for tickets! I was lucky enough to go to Galatasaray's old Ali Sami Yen stadium back in the day. Besiktas' Inonu Stadium is also another winner, never went to Fenerbahce's place. Word of advice, always go in the home end