Hello, some months ago I wrote an article about this matter, for immortal level. Now, after having win and lost many other games I'm able to give a better advice.
For "peaceful" I mean that you don't attack anyone to get his cities, but sometimes you will have to fight anyway, for defensive wars, or just to stop a AI cultural win (in 20% of all games, if you cannot bribe anyone).
Leaders.
Since I always use cottage economy the best leaders are Organized or Financial. They are equal. My second preferred trait is Creative, so I usually choose Zara or Willhelm, but any other is fine (I like Napoleon as well for the +2 happy). If I choose Org + Fin (Darius) well ... I almost always win, he's really too powerful, I've planned to use it for Deity, but for Immortal it's not fun.
Win statistics with Cre + Org/Fin are:
8 cities: 40 %
9 cities: 60 %
10 cities: 65 %
11 cities: 70 %
as you can see there is not much difference between 9 or 11, because you loose when you have Pacal/Mansa with 13+ cities or a midtecher with 15+ cities. In this case you must bribe/disturb/disrupt him since the beginning of the game.
Bad luck, boxed.
If you're boxed (it happens in 25% of all games), then you will need a quick war to liberate yourself. If you are boxed in 2-3 cities go horse archer, in 4-5 go catapults, in 6-7 go rifles (without draft or whip, which will destroy your economy. A stack of 4 trebs, 8 promoted rifles from muskets, plus other 10-15 units it's usually enough to take those 2-3 cities you miss). Don't go cuiraissers because you cannot afford to lose time to research military tradition and music. Cannons could be used too.
Cities.
All my cities are hybrid, they have cottages to support the research. I sometimes have a production city if I have HE or I have to build may units for defense. The GPfarm (if any) must contribute to research as well. Whipping is usually bad, (every citizen is useful on cottages) but if you are not Creative then it's really useful at the beginning of the game.
At every turn there should always a city which builds units (rotate them if you have not the HE) and 1-2 which build Wealth (again rotate them). Don't build buildings immediately once they are available, but evaluate how many turns they will ROI.
Initial research.
This is not different from classic liberalism race, if you meet only 2-3 civs then after Pottery/Writing go Math/Currency/CoL/CS/Paper/Edu(half bulb)/Liberalism get all the rest via trading. If you meet 4+ civs and/or you have marble the go Aes and great library.
Verify: before turn 80 your capitol must have two scientists which in 17 turns will create a GS for the Academy. Meanwhile the capitol cottages must worked by adiacent cities. Before turn 100, another city must have two scientist to build the second GS for the half education bulb. The capitol will stop the scientists after the academy.
Verify: at Immortal you will get Liberalism between turn 140-160.
If you have marble choose Nationalism and TajMahal as free tech, otherwise if you have Machinery you may evaluate Printing Press, which is better for trades.
Defensive wars.
You should always have a small stack ready to go to threatened city. Place it in the middle between border cities and verify that via roads it can reach them in 2-3 turns.
After Lib.
I usually go Economics for the free great marchant, and democracy for statue of liberty (build or fail gold). I usually skip Communism. Once I get democracy I usually start the first golden age to switch to: Universal Suffrage / Emancipation / FreeMarket / FreeReligion. US is required for production, no question asked.
Then I usually go Rifling for defence, then Biology. The I usually go to Railroad, for the production bonus. You workers must be ready on mines and lumbermills to build the railroad when it becomes available.
Happiness.
US may ruin your happiness. To save yourself every city must have two religions and two temples (you may need missionaries) and maybe a forest preserve.
Trades.
Never trade with the tech leader, never trade a tech if it's missed by the tech leader. If the leader as a tech which you need and nobody else have it, research it for the 5% bonus.
Verify.
At 1600AD you will make 1000 beakers/turn (1150 with Darius), at 1800AD 1200 b/t (1350 with Darius). Remember: There should be always a city which builds Wealth, rotate it.
Space race.
All my races are limited by research, not production (thanks to US), so when I research my last tech all the parts are ready yet. With 9 cities I usually launch at turn 340.
my path is:
Plastics, also for 3GD (if I have good production or a GE), Computers for Internet, then Satellites for Apollo (I will not be the first), then Composites or SuperConductors so that I have something to build during research, then I go straight to Fusion and start the second Golden Age with the free GE, then I research (or get it via internet) what is remaining, usually Genetics.
Espionage.
I never use the slider to increase it, but I use the free points for minor missions. In the last 20 turns I alway do counterespionage to prevent damages at my spaceship parts, while I usually allow it at the beginning of the space race, to understand who is doing it (you can see the -2000 in the espionage window), usually it's the closest civ. Another interesting mission is to sabotage towns in the tech leader. You spend zero or 40 hammers to inflict a 300 beakers damage: 3 commerce (1 + 2 freespeech) * 20 turns with emancipation * 3 science muliplies / 0.65 (AI bonus at immortal). Plus the production damage if he has US. Do that only if you are desperate.
Burocracy vs Free Speech
With this setup, before 1800AD, Bur is always better.
After 1800 AD Bur is better with Organized. Free speech will be better with non-Org (+50 beakers per turn) but it does not worth a turn of anarchy.
State property is so so, but it does not worth a turn of anarchy. The reduced mainteinance is compensated by the extra trade route of free market, and the 3-4% production bonus does not matter. It may be useful depending how many watermills or workshop you built.
GP farm
In my last games I started to use a hybrid gpfarm, usually it's a coastal city with a fish (you need a 6 food) or just any other city with a 5 food plus an extra farm on grassland.
As written above, before turn 100 it starts with two scientist. Then I start to build a forge to obtain 2 SC + 1 ENG. Then National Epic to double its production. Then Nation Park to obtain other 2-3 specialist from forests and maybe an industrial park for a free engineer. This gives 40 points per turn. Remember that at the end I need a non-engineer for the second golden age. This city must work also some cottages for research.
I usually cannot build a "true" GPfarm with 2 foods, because if I have two foods I prefer to make two cities.
For "peaceful" I mean that you don't attack anyone to get his cities, but sometimes you will have to fight anyway, for defensive wars, or just to stop a AI cultural win (in 20% of all games, if you cannot bribe anyone).
Leaders.
Since I always use cottage economy the best leaders are Organized or Financial. They are equal. My second preferred trait is Creative, so I usually choose Zara or Willhelm, but any other is fine (I like Napoleon as well for the +2 happy). If I choose Org + Fin (Darius) well ... I almost always win, he's really too powerful, I've planned to use it for Deity, but for Immortal it's not fun.
Win statistics with Cre + Org/Fin are:
8 cities: 40 %
9 cities: 60 %
10 cities: 65 %
11 cities: 70 %
as you can see there is not much difference between 9 or 11, because you loose when you have Pacal/Mansa with 13+ cities or a midtecher with 15+ cities. In this case you must bribe/disturb/disrupt him since the beginning of the game.
Bad luck, boxed.
If you're boxed (it happens in 25% of all games), then you will need a quick war to liberate yourself. If you are boxed in 2-3 cities go horse archer, in 4-5 go catapults, in 6-7 go rifles (without draft or whip, which will destroy your economy. A stack of 4 trebs, 8 promoted rifles from muskets, plus other 10-15 units it's usually enough to take those 2-3 cities you miss). Don't go cuiraissers because you cannot afford to lose time to research military tradition and music. Cannons could be used too.
Cities.
All my cities are hybrid, they have cottages to support the research. I sometimes have a production city if I have HE or I have to build may units for defense. The GPfarm (if any) must contribute to research as well. Whipping is usually bad, (every citizen is useful on cottages) but if you are not Creative then it's really useful at the beginning of the game.
At every turn there should always a city which builds units (rotate them if you have not the HE) and 1-2 which build Wealth (again rotate them). Don't build buildings immediately once they are available, but evaluate how many turns they will ROI.
Initial research.
This is not different from classic liberalism race, if you meet only 2-3 civs then after Pottery/Writing go Math/Currency/CoL/CS/Paper/Edu(half bulb)/Liberalism get all the rest via trading. If you meet 4+ civs and/or you have marble the go Aes and great library.
Verify: before turn 80 your capitol must have two scientists which in 17 turns will create a GS for the Academy. Meanwhile the capitol cottages must worked by adiacent cities. Before turn 100, another city must have two scientist to build the second GS for the half education bulb. The capitol will stop the scientists after the academy.
Verify: at Immortal you will get Liberalism between turn 140-160.
If you have marble choose Nationalism and TajMahal as free tech, otherwise if you have Machinery you may evaluate Printing Press, which is better for trades.
Defensive wars.
You should always have a small stack ready to go to threatened city. Place it in the middle between border cities and verify that via roads it can reach them in 2-3 turns.
After Lib.
I usually go Economics for the free great marchant, and democracy for statue of liberty (build or fail gold). I usually skip Communism. Once I get democracy I usually start the first golden age to switch to: Universal Suffrage / Emancipation / FreeMarket / FreeReligion. US is required for production, no question asked.
Then I usually go Rifling for defence, then Biology. The I usually go to Railroad, for the production bonus. You workers must be ready on mines and lumbermills to build the railroad when it becomes available.
Happiness.
US may ruin your happiness. To save yourself every city must have two religions and two temples (you may need missionaries) and maybe a forest preserve.
Trades.
Never trade with the tech leader, never trade a tech if it's missed by the tech leader. If the leader as a tech which you need and nobody else have it, research it for the 5% bonus.
Verify.
At 1600AD you will make 1000 beakers/turn (1150 with Darius), at 1800AD 1200 b/t (1350 with Darius). Remember: There should be always a city which builds Wealth, rotate it.
Space race.
All my races are limited by research, not production (thanks to US), so when I research my last tech all the parts are ready yet. With 9 cities I usually launch at turn 340.
my path is:
Plastics, also for 3GD (if I have good production or a GE), Computers for Internet, then Satellites for Apollo (I will not be the first), then Composites or SuperConductors so that I have something to build during research, then I go straight to Fusion and start the second Golden Age with the free GE, then I research (or get it via internet) what is remaining, usually Genetics.
Espionage.
I never use the slider to increase it, but I use the free points for minor missions. In the last 20 turns I alway do counterespionage to prevent damages at my spaceship parts, while I usually allow it at the beginning of the space race, to understand who is doing it (you can see the -2000 in the espionage window), usually it's the closest civ. Another interesting mission is to sabotage towns in the tech leader. You spend zero or 40 hammers to inflict a 300 beakers damage: 3 commerce (1 + 2 freespeech) * 20 turns with emancipation * 3 science muliplies / 0.65 (AI bonus at immortal). Plus the production damage if he has US. Do that only if you are desperate.
Burocracy vs Free Speech
With this setup, before 1800AD, Bur is always better.
After 1800 AD Bur is better with Organized. Free speech will be better with non-Org (+50 beakers per turn) but it does not worth a turn of anarchy.
State property is so so, but it does not worth a turn of anarchy. The reduced mainteinance is compensated by the extra trade route of free market, and the 3-4% production bonus does not matter. It may be useful depending how many watermills or workshop you built.
GP farm
In my last games I started to use a hybrid gpfarm, usually it's a coastal city with a fish (you need a 6 food) or just any other city with a 5 food plus an extra farm on grassland.
As written above, before turn 100 it starts with two scientist. Then I start to build a forge to obtain 2 SC + 1 ENG. Then National Epic to double its production. Then Nation Park to obtain other 2-3 specialist from forests and maybe an industrial park for a free engineer. This gives 40 points per turn. Remember that at the end I need a non-engineer for the second golden age. This city must work also some cottages for research.
I usually cannot build a "true" GPfarm with 2 foods, because if I have two foods I prefer to make two cities.
and production) for the instant civic switch. I play with unrestricted leaders and I usually choose The Netherlands because of the dykes.
