Away fan section - All European football stadiums have separate sections in the ground for away fans. The areas next to the away fans are always the liveliest place in the stadium. Security staff and police will form a line between the two sets of fans inside the ground that you'll not be allowed to pass through. You may also find your access is limited immediately outside the stadium where away fans enter, so allow extra time to get past south east corner of the Etihad.
Bag policy - Check the stadium bag policy before you travel. Allow extra time for bag checks at entry.
Drink Bovril - You should definitely try the Bovril if it's a cold day. It's a beefy hot drink served like coffee - but it's a thin, salty, beef-flavored gravy.
Sports betting - Another big difference from US stadiums is that you'll find betting kiosks throughout the concourse. Pick up a betting slip and a tiny pencil, and bet a quid on something with ridiculous odds.
Walk back to town - After the game the whole stadium pours out. The police close down the streets around the stadium and loads of people walk back into town. Join the crowd and walk because the buses, taxis and trams all get jammed up. You'll get back quicker.
Support Man City Women - In town for a few days? Check out the women's team fixtures. They typically play in the stadium beside the Etihad, although derby fixtures take place in the main stadium.