When you said in my current game, I thought that implied you started a new one. I see it is the same game, played to 1940AD.
Anyway you said you are doing better, but actually your are not getting the most out of things. This game demands that you get lots of workers and get those tiles improved.
When you are approaching Steam, you want to have plenty to rail the empire quickly. Rails mean the AI cannot invade you with any success.
I gave you are list of most of the changes I made and I suggest you look at it and think about some of them and why I did them. Mind you I am not saying this is the only way or even the best way, only a better way that you were going.
I waited the 20 turns and then attack germany in 1900AD. I already had road nealry all the non moutain tiles and rail all the cities together. Railed all the coastal tiles, so I can bring atries to bust ships or invaders.
Railed all worked tiles in the the best metros, so they get max shields and food. Hoovers was done as well.
I have taken one city and am now cleaning out the scores of units that flooded into the empire. I let Germany bring in some friends as I can handle all the civs alone at this point.
I am used to AW and making no deals and fighting scores of units every turn, if not hundreds.
The thing is not that I am going roll over Germany after I whack their incoming, but that I am trying to maximize poduction.
I posted that log for you to get some input and things to consider. Really trying to play out the game from here is not going to do you much good, only maybe fun.
To improve, I would suggest going to smaller maps. A map this size is just to easy for a human, not a real good template for playing. A std map with 8 civs on pangea or contients is better.
I would suggest posting the 4000BC and playing no more than 60 to 80 turns. Maybe post a bit of a log that shows what you were doing and why.
Post the save for the stopping point. Then it can be looked at and suggestions given, while they have a real impact on the game. The 4000bc can be used by someone to play and make a log to see how you mite change and what it would result in having.
This is one way to get much better in a short time frame. You are doing well, as many players would have posted games that could not even be won. You are in a position to win.
What you want to be is in a position of domination at this stage. That is because the fundamentals are needed as you move up to harder levels or variants.
Anyway I hope this is of some value to you. that is my goal to see if I can help others enjoy the game and get better, as long as they are interested in doing it.