OK, I can help you with your current position, too. It's just that the easiest way to improve your game a lot would be just playing the first 100 turns better, so mostly the issue is how you got there. I'm looking at your save again, starting from the event log.
- you went BW first, it's a clear mistake, always food first! (=agri). You got slight compensation in form of founding 2nd already on T30, but I'm assuming the issue is the same as in your Fred game - your capital is very small.
- otherwise early tech path is fine, though I don't think you need hunting+archery unless going for HA-attack, which would have been a good idea btw as you had horse. Going IW is nearly always a bad play. You don't even have any jungle. Locating iron does very little at this point. There are a lot of good techs to aim for (construction for war, monarchy or CoL-CS if you want to play peaceful). Going construction war is a good choice even after wasting time on IW-hunting-archery I think.
- war went pretty good I presume, but you should have wiped them out or capped them. Keeping them alive is bad for happiness and they might vassal to someone else.
- you won liberalism and took nationalism, but have nothing to show for it. You should have maybe taken something else, as Pericles already had nat since he built Taj 2T later. You could have seen this from the tech trade screen.
Onto the current position:
- you seem to be just building stuff (buildings) without a plan. Markets and grocers are expensive and doing very little for you. You are working a lot of weak tiles like 21 and even worse. Always try to whip these tiles away. You should chop forests. Never build lumbermills.
- civic choices are not good. You should be in hereditary rule. Free speech is not good, bureaucracy is much stronger. Slavery is good, but you need to use it. Mercantilism is likely worse than decentralization. Trade routes would give ~10 per turn per city, no way a specialist compensates for that. Also civic cost 7 higher. Free religion is a poor choice for diplo reasons. You should be hindu like everyone else. Pacifism is usually very good, despite having an army. are just so insanely powerful at this point of the game.
- I think you could attack Pericles with the stuff that you have now, but since you have geared up your empire to teching, I think you should go for cannons.
What exactly to do:
- sell banking to Cathy for all the money. I don't know if doing this was obvious to you, but these possibilities should always be used. Getting a pile of is great for you and her getting a tech most people have doesn't harm you in any way.
- you can get both engineering and gunpowder this turn by giving away RP to Sal and Pericles.
- I'd run full amount of specialists (5) in Agra now to get out a asap (11 turns) to start a golden age for civic switches and tile boosts.
- at steel, you should be able to conquer Pericles with cannons pretty easily. Capitulate, move to the next victim. If Fred is too powerful for you, leave him as last.