There was a point last night that I was -11gp/turn, but I had just mauled a couple barbarian villiages so I was flush with cash. Now I have research at 80% and I'm making +5gp/turn. I think it's cause of the number of cities I have. I did have to build markets and courthouses in them to get back into the black, but the more cities you have the more $$$ you can generate if you have the right city improvements. You can also set the city governor in your good income-generating cities on maximum commerce to improve cash-flow.
For happiness, you can't let your cities grow to fast, or they'll get miffed real fast. Depending on your civices, you can combat the sad faces with military units/buildings, religious buildings, and in the larger cities make some of the citizens priests. And of course you can build wonders that will improve city mood.