I can't look at the saves in game, but I can open up CivAssist.
Already in the oldest save the game is in the bag, with you having 101 cities and the Maya closest with 25. The game is then already at 1310 AD, by the way, I don't know whether you uploaded a different save from the one you intended?
I'll just make two points, I think. The first one is about your military: What I'm noticing in the oldest save is that you're researching Metallurgy, but your military is still mainly made up of Enkidu Warriors. They are really obsolete for this time. They're mainly regulars as well. Although, if you're going for a peaceful win, and you're only needing them to keep your own cities from rioting, then it's not too bad. But if you want to attack enemies, then this is the wrong army.
Your government is Monarchy here. Monarchy is a war government; it misses the commerce bonus of a government like Republic, but it also has no war weariness.
What I would say is that in this save your army and government are contradicting each other: all those low level defenders suggest a peaceful route, but your government suggests a military route.
I would suggest that, unless you're really certain you want to go for a peaceful win in a game, you keep your military updated. Also build them from barracks. The first dozen or so units may be regulars, but after that it should be veterans. That one hitpoint extra really makes a difference.
And even when you're playing peacefully, your units should be mainly attackers. An enemy AI loves to send some defenders into your territory to pillage your resources, and only attacking units offer the proper defense against this. And also when an AI sends attackers to your cities, it's better to deal with them in your own turn with your attackers than to wait for their blows to hit you. Especially if you would be in a government with war weariness, because getting attacked causes war weariness.
A second point I would make is about your map exploration: I can't see what you've been doing exactly 3000 BC of course, but I see no traces of exploration with boats on the world map. Besides what is your territory, the world is dark. Your starting point was coastal, and although Sumeria doesn't start with Alphabet, it wouldn't have been that hard to get a curragh out pretty early. My guess is that you're underestimating the importance of early contacts, probably because of unfamiliarity with the trade mechanics in the game.
The sooner you have contacts, the easier it is to trade for techs. You can even snap up expensive techs with a cheap techs, simply because of who you know. Example: you meet a civ that has Alphabet for sale, and you've got Ceremonial Burial. As Alphabet costs more, a straight swap will probably be off. But if you meet another civ that has Alphabet, it'll become cheaper, and if that new civ you've met also lacks Ceremonial Burial, then you can probably get more than just Alphabet for it.
Check your trade options often, and learn to haggle - try to get more from a civ than what they're offering.
To not explore the map and not knowing about other civs will hurt your tech pace. Maybe next time, as a training session, choose a seafaring civ and really focus on early contacts and trade. To have a program like CivAssist running with the game then becomes a must, because you don't want to call up every civ yourself every turn to see what they've got, that's too much work. Let the CivAssist alert window do that.
That's just two points, I'm sure other respondants could bring a lot more to the table.
