The discovery of Slavery technology moves me into the Ancient era.
I revolt to the Slavery civic immediately. Those wandering Neanderthals now have a use... slaves.
What is not listed on the civic screen is that you can enslave defeated units while you are running Slavery.
Slaves have three uses:
You can settle them as Citizen specialists (1 hammer per turn).
You can use them as military fodder. The Slavery promotion that all Slave units start with (and keep when promoted) gives them -75% upgrade cost, -20% strength, -5% city attack and defense, and +15% strength at the cost of dying in combat. What this adds up to is a unit that is -5% in the field, -10% against cities, and will die immediately after its first combat.
You can spend them to build buildings. This is what I do with slaves early on. A size-1 city will get 66 hammers, for buildings only, from sacrificing one slave. I use these slaves for early infrastructure improvement. My favorite is the Carpenter's Workshop, which gives +15% building production. One slave can speed up a city a good amount this way.
Next up is Poison Crafting. I would like to build the Ambusher, but this requires a Dye resource in your civilization, which I don't have.
Ngaiism is founded and spreads to Cuzco. Someone has discovered Livestock Domestication.
I discover Naturopathy, followed by Tattoos.
My difficulty drops to Prince. You can also see here how successful my Rogue has been. He only has 0.34 XP, but has picked up Combat I, Shock I, and Shock II killing Neanderthals. The Rogue started with Sentry I, Commando, and Marauder (steals 4% of enemy gold reserve on a combat victory), and gained Hunter I (+1 first strike chance) and Looter (+50% pillage gold) from buildings.
Next up is Chiefdom. I could revolt to the Chiefdom government civic, but I don't do that yet.
Someone builds a Giraffe Trainer. I haven't discovered this tech yet, but the tech of Megafauna Domestication allows you to build trainers for different animal types, including Bear, Bison, Deer, Giraffe, Mammoth, and Rhinoceros. Each of these is a World Wonder.
Tanning is next. I forget about this technology sometimes, especially with the Tannery building. Since this building causes unhealth, it's tough to want to build it early on, but it's one of the key sources for material to get Rope and Sails, which are necessary to build ships.
I pick up Canine Domestication, which will eventually lead to Livestock Domestication.
While I'm massing Dog Soldiers on Charlemagne's frontier, I get this delightful historical popup.
I'm first in power. Charlemagne is eighth. He has more points than I do. Guess who's going down.