If you are playing on the YNAEM map from these forums then Germany is actually probably the best civ due to the fact Europe is so crowded. With no war weariness in the ancient eras, just start hitting the AI fast and hard (and do not stop). An effective strategy I have found is to crank out warriors and slingers and go attack amsterdam (city state), buy a settler, and have 3 cities cranking out cheap units. Then I sweep south through France. At this point I normally have swordmen to hit spain and rome with (swordmen to spain and warriors/cheap army to rome due to the fact spains lands let them develop faster than romes so they have a better army).
By this time, I have also researched embarking, so from rome I launch a massive invasion of Greece. The final thing I end up doing is hitting russia to get a line of cities between my main core and their capital. I leave the norse and england alone to trade with.
By this time, I have technically reached the industrial age (due to beelining factories) but for the most part and still in the classical/medevil era. Shift governments to an econ focus and build up mainland Europe into a powerhouse.
The reason this works so well is the Hansa allows all those tight pack cities to get some crazy production going.
Other great civs are China and Brazil due to being isolated with great land (if playing China, take over korea from the city state and settle 2-3 cities on the china coast to box Japan out).
America has a decent start again due to being isolated, but it is hard to wipe out monty early. Russia has great room to expand, but their starting location does not allow them to fully take advantage of their UA early). England is great if you want to roleplay and use their UA. I would advise caution though as the current version of the map has cliff of dover in the starting location for London. Unless you want to change the yields to include 2 or 3 food, it actually makes the start bad because it takes up 2 tiles that you can't use for food or districts.
India is like China but a little less isolated. Their main benefit is that city states are in locations you do not necessarily want to own but are good for trades.
The hardest starts are probably Greece due to how Gorgo and the other greek guy spawn (close to each other), France (little production in capital), and Arabia (little food I believe unless they have fixed that).