Here is my successful strategy on Paragon/marathon:
Start building a militia and work your farm straight away. Reason is that the 1 hammer and commerce are more important than growing the city at this stage. With your initial militia, explore north-east where there is one tribal village, looking for extra gold. Then return your militia and merge with your new built one and overpower shusha (the independent city) which it should have just one militia guarding it. If the city has 2 pop, spare it. If they have 3, you can install a new governor which will decrease the city back to 2, which is our magic number. Work your sheep there and the plain field with 1 one of a kind, build a temple to expand the city's border and next 2 militias to protect your cities. With your survivor militia, send to the harappans to steal a worker. Plunder their resources and once you are done, declare peace and head south for another tribal village. Go back after 10 turns and try to steal another worker.
Meanwhile, research mining 》masonry first, then sailing > divination so you can build the Oracle.
Back to Babylon, after you build your first militia as explained, build the great sphinx, then the Oracle. With your worker, improve the farm, then sheep, then quarry, finally mine. Since this is marathon, you should have all your workers working together, including the recent captured. Then improve your other city sheep and dates. With your Oracle, get leverage and arithmetic. Get open borders with Assyria asap to improve your research by the extra commerce. Get writing once you research property and build edduba in both cities asap. After that; focus on great people which should give you a great prophet or great scientist to bulb for calendar and an extra tech. Then go for smelting 》construction. After that is pretty straight forward.