Here is what i have been using lately, its very simple and very effective. I can beat anyones science and tech output with half the cities.(spaceflight at 1200 AD, 1x 1x, king, no wonders, tech trading, huts or caravans to other civs) Here is step by step what you do.
1. build settlars and go make cities SPACED OUT, connect them by roads.
2. go for monarchy, as soon as you get it irrigate everything and go for trade.
3. once you have trade go for rep, by this time you should have 15 or 16 cities with about 16 settlars. (about 1 ad and all your land should be transformed and irrigated + roads)
4.set your inner cities to build caravans.
5.once in rep send carvans from all your cities into your capitol.
6. Go for mono, build libraries & temples & market places. keep all your cities celebrating with 20% luxeries.
7. go for construction & sanitation. By the time you get them most of your cities should be size 8, then you celebrate your cap up past size 20. Once you have done this ALL the trades routes in EVERY city will grow by one, forcing them to celebrate as well.
8 switch to dem at about 300 AD and you should make $400 gold per turn and 2 turns a tech and by that time your far ahead of everyone else. Use all the extra gold to buy improvements and go for exchanges and univeristy. They buy those in your huge cities.
Here is a pic of a game i played with carnide today, i am 1 tech from railroad here. I have dem, mono, navigation,economics, university etc. About 20% less cities then everyone else, half the maintaince costs, but double the income and science. In this pic i am making 800 gold a turn and 2 turns a tech at 50% science
