Thanks for the tips above =)
What about city placement, when expanding, how far away/close should one build the next city? Also what tiles should one place the city on? I know that cities close to river/water is a good thing, but what kind of yield should one have on the tile you place the city on? Or doesn't that matter to much, as long as you have good tiles with resources around it?
I generally aim to start off a game with a 3-5 city core. Typically I'll try to keep the spacing between the cities around 4-5 tiles. More importantly, for the first few cities (prior to researching iron working) I'll be looking for the following (in about this order)
1) Can work a new unique luxury (required for happiness - offsets the happiness penalty from founding a new city, which is fairly critical until you've got religious/cultural/tech that build happiness)
2) Good production capability (forests w/hills best, hills 2nd, forests 3rd). Lots of forests early in the game is really nice, as you can chop down forests for instant production, which can make a huge difference in the early game when your hammer production is really low.
3) City site is on, or at the very least near, a river, or a coastal spot with water resources (fish, or water luxuries) (helps build a good commerce city). Having a ton of commerce potential is about the only reason why I would found a city early on that didn't have both #1 and #2 above. Gold is hard to come by early, though you'll be rolling in dough late.
4) Food sources - food is pretty easy to come by, so I typically don't worry about access to things like deer, wheat, etc. You'll find that most city sites that meet 1 or more of the above 3 will have adequate food tiles to work nearby.
Ideally, of course, you'll have 4-5 good city sites that meet all of the above. Yield from the tile you actually settle on doesn't make much difference (on a hill will start you with an extra hammer for example). Try to time your settling so that you have a settler either out or about to come out when iron working is finished. If the random gods were unkind and you don't have any iron already near your settled cities, that'll let you bring it in relatively quickly.