First the good things...
-You are the scientific leader. No other civ that you know of has a tech over you
-You have the two reources of the early game, iron and horses
-You have a big piece of land to settle with all kinds of terrain. That tundra looks bad, but it will surely have oil and maybe also rubber. You can also grab desert tiles and jungle spots. Needed for saltpeter and rubber.
-You are building harbors, sensible for a seafaring civ
-You have embassies
Things that I noticed:
-you need more workers. They are probably the most underestimated unit of them all. They will improve your land and make it grow. You are industrious, but that doesn't mean that you should build less workers. They will be extra important when you start to railroad your lands.
-You have connected your empire with roads and built a few mines, but you should have improved your centre a bit more. Tip: when you are on a tile create an improvement first (irrigation or mine) and build a road immediately after that
-You have a lot of plains and you are mining it. You should irrigate it, because that will allow your cities to grow. The irrigation can only be done next to fresh water, do you should start with plains next to that and then work your way to the rest of the plains.
-You decided to have an almost optimal city placement, which is good when your cities grow to size 20 and you all the available tiles. However, your land is not so suited for fast growth, so a tighter build with more overlap might have been a better choice. 12 tiles per city, to allow them to grow to use all tiles at size 12 (maximum before the industrial age) is a good number.
-I am a big fan of fast units (horses and knights). I would only build those and the occasional spears and pikes.
Tips for the near future:
-I would research towards Republic and switch to that government as fast as I can. It is the best government in most situations.
-Currency is important to get Marketplaces and Construction is needed for aquaducts, to have the cities grow past size 6 (giving you more free units: more income).
-Just settle the tundra with about 4 cities. They won't be very productive, but will help to pay the army. As seafaring it is best to build on the coast (extra commerce).
-You have room for two cities SW and NE of Utica
-I'd settle south of the horse, on the river SE of the wheat.
-Try to grab the complete east of the continent.
I'm confident that you can win this. You have played a steady game so far and you show that you understand the basics. Only there's so much to learn and understand.