After all the help you got from the first two posts, I'm not sure I need to add anything.
Take it in baby steps. Start off with the minimum setting for the Barbs, 3 players, large map. That should give you some time to get use to what the higher difficulty level does to you. You'll learn real quick that unhappiness is a major problem. Build a couple units to keep the peace while in Monarchy.
Expand quickly. Usually ever other unit should be a settler. Early on this does two things, it helps you get expanded quickly, and keeps your cities population low.
Try to build caravans and get happiness wonders (hanging gardens, oracle, Mich's chapel, etc) early on.
As Moof said, build caravans and deliver them; to your own cities if you have to. This gives you more money and science.
Also as Moof touched on, learn the art of rush buying units and use it always. This saves you valuable turns in the game.
The Ai is still the Ai, except now they get even better bonuses for building units and getting tech.
Use diplomats and spies to steal tech if you ever get too far behind in the tech race.
That should hopefully give you a good base to work off of. Learn the tricks of the game by looking through the War Academy that Moof pointed out, Odeo turns and the such can save you tons of agony in the game.
Good Luck!
P.S. Once you get a handle on the 'small' start, add more players and get use to the full amount of players before you add on higher difficulty levels of barbs.
