Advance apologies for the tl:dr
I'm playing a vanilla game as FDR on a huge Great Plains map, om Marathon. My start was mostly brown, a lot of hills, and plains with a decent amount of rivers. No green to speak of, but a good amount of cows. I was planning on using FDR's Wonder bonus to my advantage especially with all the hills, but I didn't do a good job on the tech front, as well as due to a somewhat isolated start, I got too wrapped up dealing with barbarians.
I fell behind pretty quick, I had no forests to chop, and all the brown made growth difficult. I had to alter my game plan somewhat, I did a lot more begging and demanding from the other civ's, and decided to be a bit more warish than usual. Luckily, my production level, coupled with the constant barbarian fighting allowed me to build a substantial army of experienced troops fairly early. I had CR III with Combat Swordsmen and Macemen in good supply. Most of the other civs had lots of green to live on, but not a lot of hills, so they tended to have smaller armies. during peacetime, I kept a defensive pat with Cyrus, as he was the top dog.
I took out Alexander, Tokugawa, Napoleaon and Saladin. I pillaged a lot more than usual, and was very selective when keeping captured cities. Since my first few cities were production machines, I was able to concentrate a lot of the others on either wealth or research which at least kept me in the game, and I would sometimes beeline ahead to get something no one else had as opposed to something I probably needed, military wise, gambling on my armies experience to get me through. I then could trade to backfill what I was missing.
Whacking Saladin was key, he had 3 Holy Cities, with Shrines, so once they became mine, the missionary spam began and coupled with building Wall Street in one of them, my tech rate skyrocketed and I was able again to leap frog a couple of techs and trade to get myself up to parity. I'm stil a bit behind, but I'm right there, I have enough gold coming in to rushbuy anything I need. This has been a fun game for me. I've been playing Noble, about ready to move up and I had to think a lot more than usual.
Driving your economy in to the ground can be hard to recover from. Micro-manage your cities. Focus on producing money and specialize a few in to science to not fall very behind until you can get enough courthouses and markets to get the money flowing again.
. At what point in the game and what are the particular circumstances??
and 
) because you spend less time with units and buildings in the city que........all you need is que it, wait one turn, then whip it. Plus you can chop/que while doing this which is very powerful.
