So what do you do to improve your economy if you've already built a market,grocer,and bank in the villages?
You have to have citizens assigned to work the tiles with cottages. This is done in the city screen. The commerce multipliers won't do you much good if there's very little commerce to multiply.
Also, I know this is gonna be a n00b question, but at what populations is the BFC expanding...and how many tiles in each direction is that village able to work? This question is assuming that the village in question is not abutting another village,competing for workable tiles. The reason I ask is, I settled a village with 3 gold resource tiles around it, but had to move a bit away from 2 of them so i could include a rice resource for food. Now the village is 14 pop,has a couple world wonders and has yet to expand its workable tiles (to the right in the village screen where you click which tiles to work) to include these other 2 gold resources. I'd like to mine them for the big money gain,but I'm not able to. Why?
The BFC will expand almost indefinitely, but each border expansion requires more
culture, not population, in order to expand. You can only assign citizens to work tiles within the 21 tiles around the city, including the BFC--essentially a 5x5 box, excluding the 4 corners:
XOOOX
OOOOO
OOOOO
OOOOO
XOOOX
Any resources outside of that "Big Fat Cross" can be claimed by eventual border expansion, but cannot be worked by a citizen unless they fall into the BFC of another city. You may be able to trade those resources for other resources you lack, or for gold per turn, so it's still worthwhile having them.
Trading surplus resources for gold per turn (GPT) is another way to help your economy. So are trade routes.
All of these concepts--commerce, culture, the BFC, etc.--are covered in more detail in my Beginners' Guide (link in my sig). If you haven't read it yet, you might want to have a look.
Oh, I did manage to found Christianity and spread it to a couple other civilizations and also to a couple of my village. When I sailed to the other continent, one of the things I threw into a negotiation with Julius Caesar was "convert to Christianity".
My question, do I receive income from the civilizations I spread Christianity to, or just from the Roman civilization's towns because they "converted"?
Man, soooo many different concepts in this game!!
It is a very complex game, and that's why so many of us love it. Again, I recommend having a look at my Beginners' Guide.
To obtain income from spreading a religion, you must build the shrine in the holy city where the religion was founded. To build the shrine, you must produce a Great Prophet, a type of Great Person; send him to the holy city and one of his/her action buttons will be to build the shrine. Once built, that city gets 1

for every city, foreign or domestic, with that religion present. Make sure you build all the commerce multipliers in that city, and if the religion spreads enough, you will eventually want to build Wall Street there.