Hey KJades,
So, for fun I'm playing a quick game of Babylon with Immortal, Large Map (plus an extra AI, Pangea, Random Personalities, Raging Barbs) to get some immediate comparison. Mind you, this isn't a demonstration of "Optimal" Babylon, merely "basic" Babylon to win on Immortal. Standard Speed.
Had a bit of a Trollish start, Jungle Coastal, only crabs and whales, very low production capital. Very low production game, but a very easy Diplo game as I went Coastal Tradition and sold 6 crabs to AI on a consistent basis and Allied with a few Mercantile CS early (Barb camp teams of scouts and bowmen).
So, even with a Meh start, hitting T110 Education is pretty straightforward with Babylon. 3-city NC by T90, followed by T174 Ideologies, and T198 Labs. Coastal Tradition, planting 2 Academies in Jungle Cap, buying Science buildings in Cap ASAP, selling luxes and strategics to AI, bribing most aggressive neighbors to attack elsewhere.... about as basic as it gets.
I ended up going 5-cities with a fun shape because I could settle far away a 2-lux distant city (which I love doing), so my 5th city isn't even planted by T110. Not an impediment, so long as you have the happiness (which I had from Merc CS Allies), and can pump cargo ships into it and buy an Aqueduct.
Even with just one Lab, and only 2 policies completed in Rationalism, I'm over 700 Science on T200. So by Turn 300 on Epic, you want that target. I'll be at 1200+ before too long. And 1500+ By T250.
Here is T110
http://steamcommunity.com/sharedfiles/filedetails/?id=499519772
And here is T200
http://steamcommunity.com/sharedfiles/filedetails/?id=499519837
I think from seeing your responses above, some "basic" skills you need to work on are 1) learning to go max growth, 2) Learning to sell possible goods to AI, and 3) Acquiring CS or AI happiness.
Inner trade routes (particularly cargo ships) are amazing with food, and more amazing with free Aqueducts in Tradition. In this game I have a 16-pop Jungle capital by T110. When you learn how to grow as fast as possible with internal trade routes, you'll realize that you'll burn through happiness quite quickly and should only settle 4-6 cities with Tradition.
Selling stuff to AIs is a bit of micro and relies on good scouting, particularly on large maps to find trading partners and develop DOFs if possible. Finding happiness is a game tactic that will develop as you figure out how to time CS quests, send archers far and wide for camps, and getting AI gold to buy a CS Ally.
Have fun