Step 1: find a city location that is coastal, with 6 cows and reasonable shields.
Step 2: Build stuff.
That game turned into a deity OCC, which I will write up properly later.
The rest of this thread will be a proper guide to winning via 20k on standard and bigger maps, anywhere up to demigod. It can work on higher levels, it just requires a bit more luck and more effort.
Settings: 70/80% archipelago, warm, wet, 3 million, no barbs, min aggression
Civ: Pick your favourite seafaring civ. Either Byzantines for the cheap buildings, the free tech, and the SGL chance, or Spain for the cheap buildings & minimal anarchy. Spain has better starting techs, as the AI will almost always get Bronze working for you, Spain's disadvantage is that this method almost guarantees a despotic GA.
Opposition: Minimum civs. Definitely nobody with Alphabet, my preference is lots of EXP civs, no SCI civs, and no REL civs, to ensure CB can be traded, and so hopefully you can build Oracle. On a large map, that usually means Zulu, Mongols, America, China, Aztec, Inca. My inability to remember who is who often results in Arabs replacing the Inca, as they're both pink.
Start required: Fresh water, at least one food bonus, reasonable production at size 12.
Research: min on writing, max on Philo, then either Monarchy, Republic or Literature as the freebie, depending on what you can trade for.
Build order: Curragh, worker x 2 or 3, barracks that will be changed to colossus.
MMing: max growth. Irrigate the food bonuses, hopefully reach +5 food.
Explore with the curragh, if you only find 1 AI by the time the barracks is about to finish, you'll need to give up 100 or so gold or alphabet to get bronze working. Find 2, and CB will be enough on its own. Find none, and you'll have to start again. Switch build to colossus.
After the colossus: At least 1 settler, possibly temple & 1 or 2 warriors, possibly another curragh. Remember that any food in the box when you build a settler at size 7 or 8 will disappear, and try to avoid it. That settler will crank out workers & warriors for MP in the capital.
After the capital builds the settler, you should be able to trade for Masonry, so start on the Pyramids. Get the capital to size 12, on all improved tiles ASAP, by joining workers. If Mysticism appears, trade for it, switch the build to Oracle instead of Pyramids. You should get one of the 2, which will trigger a despotic GA.
Concentrate on researching for wonders, keep your capital building culture, and your 2nd city on settlers, etc, to expand to fill your island. You'll be vulnerable to attack once Map Making appears, if you're worried about your ability to defend, get a psuedo war happening. Declare on a more distant neighbour, get your closest neighbor and biggest threat allied in with you, and it should be all good.
Once you're into the MA, I usually beeline for Education, then either Music Theory or Astronomy, followed by a beeline for Shakespeare's. Assuming your military looks better, a psuedo war should hopefully result in a steady stream of landings to leader fish on in order to get heroic epic.
Other tricky bits: S o Zeus, at 4cpt for 200 shields is very nice to get. Often, you can get it even if you don't have ivory. Build Great Lighthouse, to trade over sea, and hopefully trade for Ivory from somebody without maths, but with harbours.
By the early MA you should have guaranteed a win, and be simply improving your date, and avoiding losses via 100k, conquest or UN.
I'll post an actual game with some pictures later, but my last few games are still saved, all using this method, so they make a decent guide for approximate dates, as given by CA2.
Game 1: Standard, Deity, Spain (the 6 cow game above)
Palace: 3900 BC
Colossus: 2270BC
Oracle: 1675BC
Pyramids: 1325BC
Mausoleum: 1125BC
G Light: 825 BC
Temple: 775 BC
Library: 690 Bc
G Library: 290 BC
Hanging Gardens: 50 BC Win date at this point: 1938 AD
Eventual date: 1670
Game 2: Large Deity, Spain (1 cow, no other food bonus)
Palace: 4000BC
Colossus: 2030 BC
Temple: 1790BC
Pyramids: 1750BC (Changed plan due to an SGL)
Oracle: 1400BC
Mausoleum: 1175BC
G Light: 775BC
S o Zeus: 510BC
Library: 470 BC
G Wall: 190BC
Colosseum: 170BC Win date at this point: 1958
Eventual date: 1655
Game 3: Large, DG, Spain (4 cow, low shield)
Palace: 4000BC
Temple: 3150BC - There must have been a reason to do this. I suspect it involved chopping a couple of forests, and getting a settler out first as there was a site for a second city to use irrigated cows to crank out workers. Not sure though.
Colossus: 2150BC
Pyramids: 1450BC
Oracle: 1150BC
Mausoleum: 950BC
G Lib: 925BC (love those SGLs)
Library: 825BC
G Light: 510BC
S o Zeus: 310BC
Hanging Gardens: 30BC Date at this point: 1854
Eventual date: 1610
Game 4: Large, sid, spain (2 cows, 2 mountains)
Palace: 4000Bc
Oracle: 1990BC - missed colossus by a turn or 2, super quick tech pace meant I could trade for mysticism.
Temple: 1910BC
Pyramids: 1750BC (Writing SGL.
)
G Light: 1150BC
H Gard: 875 BC
Colosseum: 750BC
Library: 570BC
G Lib: 250BC Date at this point: 1971
Eventual date: 1792. The Zulu were going to win this game via 100k, they were about 1500 culture below doubling the americans, and gaining at 100 per turn. Slowing them down was going to be very tough, so around 1610 or so, I decided to speed the americans up instead. I gifted them all my cities except the capital, and it worked. Finished the game with the americans on 87k, Zulu on 168.5k. I was very happy with that bright idea.

Step 2: Build stuff.
That game turned into a deity OCC, which I will write up properly later.
The rest of this thread will be a proper guide to winning via 20k on standard and bigger maps, anywhere up to demigod. It can work on higher levels, it just requires a bit more luck and more effort.
Settings: 70/80% archipelago, warm, wet, 3 million, no barbs, min aggression
Civ: Pick your favourite seafaring civ. Either Byzantines for the cheap buildings, the free tech, and the SGL chance, or Spain for the cheap buildings & minimal anarchy. Spain has better starting techs, as the AI will almost always get Bronze working for you, Spain's disadvantage is that this method almost guarantees a despotic GA.
Opposition: Minimum civs. Definitely nobody with Alphabet, my preference is lots of EXP civs, no SCI civs, and no REL civs, to ensure CB can be traded, and so hopefully you can build Oracle. On a large map, that usually means Zulu, Mongols, America, China, Aztec, Inca. My inability to remember who is who often results in Arabs replacing the Inca, as they're both pink.
Start required: Fresh water, at least one food bonus, reasonable production at size 12.
Research: min on writing, max on Philo, then either Monarchy, Republic or Literature as the freebie, depending on what you can trade for.
Build order: Curragh, worker x 2 or 3, barracks that will be changed to colossus.
MMing: max growth. Irrigate the food bonuses, hopefully reach +5 food.
Explore with the curragh, if you only find 1 AI by the time the barracks is about to finish, you'll need to give up 100 or so gold or alphabet to get bronze working. Find 2, and CB will be enough on its own. Find none, and you'll have to start again. Switch build to colossus.
After the colossus: At least 1 settler, possibly temple & 1 or 2 warriors, possibly another curragh. Remember that any food in the box when you build a settler at size 7 or 8 will disappear, and try to avoid it. That settler will crank out workers & warriors for MP in the capital.
After the capital builds the settler, you should be able to trade for Masonry, so start on the Pyramids. Get the capital to size 12, on all improved tiles ASAP, by joining workers. If Mysticism appears, trade for it, switch the build to Oracle instead of Pyramids. You should get one of the 2, which will trigger a despotic GA.
Concentrate on researching for wonders, keep your capital building culture, and your 2nd city on settlers, etc, to expand to fill your island. You'll be vulnerable to attack once Map Making appears, if you're worried about your ability to defend, get a psuedo war happening. Declare on a more distant neighbour, get your closest neighbor and biggest threat allied in with you, and it should be all good.
Once you're into the MA, I usually beeline for Education, then either Music Theory or Astronomy, followed by a beeline for Shakespeare's. Assuming your military looks better, a psuedo war should hopefully result in a steady stream of landings to leader fish on in order to get heroic epic.
Other tricky bits: S o Zeus, at 4cpt for 200 shields is very nice to get. Often, you can get it even if you don't have ivory. Build Great Lighthouse, to trade over sea, and hopefully trade for Ivory from somebody without maths, but with harbours.
By the early MA you should have guaranteed a win, and be simply improving your date, and avoiding losses via 100k, conquest or UN.
I'll post an actual game with some pictures later, but my last few games are still saved, all using this method, so they make a decent guide for approximate dates, as given by CA2.
Game 1: Standard, Deity, Spain (the 6 cow game above)
Palace: 3900 BC
Colossus: 2270BC
Oracle: 1675BC
Pyramids: 1325BC
Mausoleum: 1125BC
G Light: 825 BC
Temple: 775 BC
Library: 690 Bc
G Library: 290 BC
Hanging Gardens: 50 BC Win date at this point: 1938 AD
Eventual date: 1670
Game 2: Large Deity, Spain (1 cow, no other food bonus)
Palace: 4000BC
Colossus: 2030 BC
Temple: 1790BC
Pyramids: 1750BC (Changed plan due to an SGL)
Oracle: 1400BC
Mausoleum: 1175BC
G Light: 775BC
S o Zeus: 510BC
Library: 470 BC
G Wall: 190BC
Colosseum: 170BC Win date at this point: 1958
Eventual date: 1655
Game 3: Large, DG, Spain (4 cow, low shield)
Palace: 4000BC
Temple: 3150BC - There must have been a reason to do this. I suspect it involved chopping a couple of forests, and getting a settler out first as there was a site for a second city to use irrigated cows to crank out workers. Not sure though.
Colossus: 2150BC
Pyramids: 1450BC
Oracle: 1150BC
Mausoleum: 950BC
G Lib: 925BC (love those SGLs)
Library: 825BC
G Light: 510BC
S o Zeus: 310BC
Hanging Gardens: 30BC Date at this point: 1854
Eventual date: 1610
Game 4: Large, sid, spain (2 cows, 2 mountains)
Palace: 4000Bc
Oracle: 1990BC - missed colossus by a turn or 2, super quick tech pace meant I could trade for mysticism.
Temple: 1910BC
Pyramids: 1750BC (Writing SGL.

G Light: 1150BC
H Gard: 875 BC
Colosseum: 750BC
Library: 570BC
G Lib: 250BC Date at this point: 1971
Eventual date: 1792. The Zulu were going to win this game via 100k, they were about 1500 culture below doubling the americans, and gaining at 100 per turn. Slowing them down was going to be very tough, so around 1610 or so, I decided to speed the americans up instead. I gifted them all my cities except the capital, and it worked. Finished the game with the americans on 87k, Zulu on 168.5k. I was very happy with that bright idea.