I could write a book on this.
- Built cities without escorts
- Built any wonder no matter where I was
- never micromanaged
- Waited for all of my cities to hit size 8 before building acqueducts (same for size 12) because I thought it would maximize food tiles that a city has.
- terraformed almost everything to grasslands rather than 2/3 hills, and 1/3 grasslands. (which I just found out works wonders)
- irrigate grasslands during despotism
- change governments just because I researched them
- roaded first, then irragated
- never built roads for settlers
- railroaded the edges of my empire first, then inward to the capital last (no city-to-city links)
- cleared forest in the early game
- railroaded forests
- mined deserts
- never scouted land for city placement
- irragated/mined/roaded all tiles in a city radius first, even if it couldn't use it
- Build queue was essentially defense (phalanx)-temple-barracks-market-bank etc. (and any other improvement)
- built a wonder in a seperate city (except the science ones)
(there could be more..

)