Another Civ 4 try

I've started a new game of Civ 4, and I'm frustrated because I've lost a few games in a row. The problem is, I keep getting too impatient and either try and expand my cities too quickly, or try and take over other civs too quickly. In my current game, I'm playing as the Persian empire. The other civs are the Incans, the Americans, the Zulus, the Koreans, the Japanese, and the Celts. At this point, the year is 1451 AD, and I have 7 cities. I just finished researching Education, and I'm making a beeline for Industrialism. It may take me a few hundred years, but I hope to get there before someone declares war on me. I think the Zulus are close to invading me, so I'm starting to build a small army made up of a few swordsmen, a couple catapults, and trying to add some musketmen. Most of the world has been settled so there's not too much of an opportunity to build new cities. I'll have to take over a couple cities culturally, otherwise I'll have to take over militarily. I can win the game via a cultural or conquest victory, but at this point, it looks like a cultural victory would take too long. So I'll build up an army and see how it goes. Speaking of going, Go Leafs Go, and take the Argos with you