Learn to build more cities which run efficiently and learn how to improve those cities via Workers! The cities are the building blocks for everything in this game. Everything you build is taking too long because your cities are either too few in number or arent' developed correctly (i.e developing tiles correctly to produce shields/food)
Go to the War Academy on this website and read the articles. There's no secrets, it's just simple techniques and steps that everyone here has learned and continues to learn.
Everybody's happy to share and happy to help, but you got to bring a little more to the discussion than "hey I suck, tell me how I can play better!"
Good luck...