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.