Great tips. A few of my own.
1) Faster wonders. Build something big. Start with a normal improvement. The bigger the better. Sacrifice population to max it out then switch to the Forbiden Palace until you get the advancement needed for the wonder you want. Back fill the sacrificed pop with workers.
2) When in doubt build workers. Founding cities,especially in enemy teritory is easier if you build roads and improvements before you found the city and then assimilate 3 workers into it. Instant well established pop 4 city.
3) Late in game build and use bombers. Founding a city on an enemy continent is faster if you fly in bombers and disband them to make walls, temple, harbor and airport. Then fly in the teaming masses.
4) Think hard before disbanding. A cluster of obsolite units can rush across a border, especially if they are horsemen, and plunder the roads connecting civ to thier iron, saltpeter, etc. Before tanks a unit can still kill only one unit at a time. A rush of 20 horsemen and charriot is quite impressive vs the amount you would get in shields for disbandment.
5) If you sell a tech sell it to every civ. If you don't they will.