Biggest mistakes:
1) Attempting the "2 warrior" gambit in the early game against France. When it failed, I spent the next 1000 years catching up (no, I did not reload when it failed). Waiting for swordsmen would have been a better option.
2) Trading contacts between civs right away. I should have kept them isolated longer to slow down tech.
3) Not really a mistake, but on this map building cities early on in ICS style would have helped a lot.
Best moves:
1) Recovering from my earlier mistakes through a mixture of diplomacy and good tactics in warfare. At one point, I was at war simultaneously with France, Russia, Japan, and Greece (at their instigation, of course).
2) Having two elite spearmen defend a city I knew I couldn't hold on Greek mainland until a great leader popped out, then rushing a galley to bring him back to mainland and rush the Forbidden Palace. This was the turning point in the game from "I'm being clobbered" to "I'm somewhat equal with the others"
3) When the rest of the world entered a feeding frenzy on Japan, I waited until their units were gone and then entered the war myself, capturing all their cities at minimal loss.
4) Instigating wars between the other civs that forced them into Communism; this was how I got a tech lead, followed by...
5) Researched tanks first. End of game.
Russia, Egpyt, then Greece fall. Now building up score for a 2050 finish. The current 1580 or so score isn't very good. but I've got another 100 turns to increase it.