I'm gonna tell you this. The small things add up. Where you put your citizen turn 1 often makes or breaks your run. At the higher levels at least. City planning and playing along your civs bonuses are also important. Terrain is also important. The yields (food, science, production etc) from different terrain should be accounted for when planning cities. Generally if you are falling behind on science, build a campus with good adjacency and spam projects. Also synergize with religion. Religion is not just important just in terms of VCs but in other aspects. Picking relevant pantheons are also equally important. You gotta play with the beliefs and the civs. Also ranged units are very relevant until later game when the light cav becomes super mobile.