So the most commonly advised strategy is to have a capital with lots of cottages, run Bureaucracy and use all the commerce from cottages to tech, while also running a GP farm to get great scientists to bulb towards Liberalism.
But what to do on maps that don't suit this way of playing. For example where there are no or very few riverside tiles, lots of hills or plains, and land that is just generally bad for building cottages?
If you have a lot of food and stone, then Pyramids/Representation/Caste System works well for generating beakers through specialists, and if you have a lot of coast then the Great Lighthouse can generate a lot of commerce through trade routes, but there are a lot of times when neither of these work - eg you don't have the right setup, or these wonders get built before you can get to them.
The only thing I have come up with is to Oracle or tech metal casting, build forges and then tech by building research - but this is less effective because the forge is the only hammer multiplier while an Academy is a much more effective science multiplier.
Some tactics I can add:
-Especially if you're industrious or have stone/marble, build as many wonders as are available, and if that wonder wouldn't be especially useful to you purposely lose the race to build them and get a gold boost from failing to build them. Also in using this approach you can chop forests towards the wonder in a checkered pattern to maximize their regrowth.
-Consider an espionage economy. This starts with the great wall. Generally you'll want to infiltrate an advanced neighbor with your first spy. The amount of espionage gained is huge early on, and it will greatly reduce the espionage costs of all missions after that so you can generally get many technologies just from one great spy.
-Perhaps it goes without saying, but scout your neighbor's land and consider invading the one with the best economy if you can gain a military advantage.
Otherwise: I play on random huge immortal maps, mostly fractal or hemispheres. My cities fall into four specialization types: Cottage, food, production (subtypes military and non-military), hybrid. I vary rarely cottage my capital because it tends to be better suited to one of the other specialization types. Plus in the early game I'm using it to churn out settlers or an axe rush, or the great wall, depending upon the situation. Converting it into a cottage city after that usually seems like a waste but if the surrounding land is really marginal, I'd consider it and pat myself on the back for not just reloading.
I spend a lot of time on city planning early in the game. The first priority is usually to have both a food and a production city (usually, the capital falls into one of these categories). The food city will produce settlers/workers early on, and great people later. The production city will spend almost the entire game building military units. After that, almost every city is dedicated to commerce unless I need more military units faster.
Plains can work for cottage cities if you have food resources to compensate for it, e.g. try to get 2 or more food resources in the fat cross.
Here's a description of how I find optimal cottage locations: I zoom out and go into the strategy layer, draw out potential fat crosses, and give the city a score for the types of cities I'm considering.
For a cottage city, in the long run, you want to maximize the number of cottages the city works. For grass tiles, I write a c on them. For a river, I put a dot above the c. For any tile that requires extra food I put a - for every food, and for each extra food produced I put a I (vertical line). So a plains tile is c-, and a flood plains tile is cI (with a dot). First I count the regular c tiles, then figure out the food balance, and figure out how many additional cottages can be worked.
For financial leaders I give an extra c for every 4 cottage river tiles that will be worked, and non-financial and non-cottage it's every 6 river tiles worked. For coastal tiles I'll give an extra c for every 4 tiles if financial, otherwise every 6. I generally give a double c for gold/gems, and think of them as having a short-term advantage in commerce.
After all this I can calculate the "c-score," which is the maximum cottage-equivalents that can be worked there... A very good score is above 16 or so, but even 10 is usually worthwhile unless the city is far away. Also consider food excess... An area with no resources and all grass can make a decent cottage city, but growth and infrastructure development will be slow (may help to temporarily use a river tile for even a crappy 3 food farm, since that would represent a 50% increase in growth rate in that situation)... so I consider food and production as well for tie-breakers.
Food cities are graded by total possible excess food (before biology) in the long run, and highest ratio of food excess to population for short-term.
Production cities are graded mostly by production per population, with 20 production per 10 population considered decent.
I check the demographics tab pretty often to see where I'm lagging compared to other civs.
For example, there is a reasonable amount of grassland, but only a 1-tile river near the coast - is it still worth building a lot of non-riverside cottages?
In the long-run, number of cottages matters more than whether they're river or not. Once developed, it's like the commerce difference between gold and gems (gems often do better actually because they don't require as much food to support them).
