Yes, Brude, city specialization becomes more and more important as you play on more difficult settings.
You have your military production, economy center, research center, Wonderspammer, Great People Farm and so on. You need to plan ahead which Wonders to build where (only 2 national wonders per city allowed).
I think the game becomes interesting at Prince-level, before that it's just about learning the basics.
I play on Monarch/Emperor and can win fairly comfortably on Monarch. Playing on Emperor is fun sometimes if I have the time to really get into it, but usually it's too much of a chore. The harder the setting you play, the more attention to micromanagement is needed.
Try out the Cottage economy first, it's easiest to begin with. Pick a leader with the Financial trait. Build cities with lots of grass plains in the BFC (big fat cross) and cottage them. In the long run this will give you huge amounts of commerce.
The Specialist Economy can be more effective early in the game. Build the Pyramids quickly and get Representation and make specialists in your cities from the food surplus. This requires cities with lots of food resources and preferably floodplains tiles in the BFC.
Here you need to start counting food income for each city. Each population in the city requires 2 food and also 2 food per specialist.
A floodplain will give you 3 food (4 if farmed) and more as the game continues (Biology for example). So for each farmed floodplain you can have another specialist in that city. A Pig tile gives you 6 food (I think) so that's another two specialists.
Specialists generate Great People Points and these will give you Great People every now and then which can be settled in your cities and boost them to absurd capabilities. Great Scientists goes into you research city and Prophets are great for your production cities.
A leader with the Philosophical trait will double the Great People Points earned.
If you settle all Great People in the capital (for example) you'll get a city with skyhigh production capacity which can churn out Wonders really fast. This is called a Wonder Economy/Settled Specialist Economy. Works great together with Bureaucracy. Your entire civ is based on one powerhouse city.
This site is your best friend:
http://forums.civfanatics.com
It's been a really long time since I played Civ4 now, so I don't remember all the finer details now, but now the old Civ addiction is starting to kick in again. :D
Edited by Papirolle, 26 February 2009 - 05:42 AM.