Connecting your cities up with roads for trade? Building markets and using specialists in them? Improving resource tiles? Monitoring the dispersion of your civilians so that they are working the right tiles ? (leaving it on auto often doesnt pick the best selection in my experience, so I manage all my cities civilians myself), keeping building projects in line with your income?
I did not know you could use specialists in the buildings so thanks for the tip and will take a look this evening.

, I am playing a huge earth map game, i'm up to 2010 so not far to go... but their is a known bug which screws the game up when you get too many cities (65 or 70) where you reach a kind of cap, you can continue playing but not take any cities, if you do the game crashes and it is even possible to corrupt the save game (I think I corrupted mine just by reloading loads of times to see if I could proceed).