My first two attempts at Monarch level, I was stuck on a small continent (large island). I settled into third place behind the two civs that were able to conquer large continents, and I could not move ahead. I launched successful invasions, but while I was at war someone else (usually my useless ally) built up an unassailable tech lead.
In my third attempt, I am the Iroquois on a large continent with the Americans and Aztecs. Thanks to the mounted rider (best special unit I've tried), the Aztecs are gone and the Americans will soon follow. I got a great leader to build the Forbidden Palace, I have corruption under control, and I have a lead which I expect to maintain. This is the sort of winning position that I could not overcome in my previous games.
Basically it looks as though taking over another good-sized continent is very difficult without a strong technology lead(I've never seen the AI do it). My conjecture is that at Monarch or harder difficulty, you should give up if you find no one to conquer on your initial continent. At Regent level such games are winnable.
In my third attempt, I am the Iroquois on a large continent with the Americans and Aztecs. Thanks to the mounted rider (best special unit I've tried), the Aztecs are gone and the Americans will soon follow. I got a great leader to build the Forbidden Palace, I have corruption under control, and I have a lead which I expect to maintain. This is the sort of winning position that I could not overcome in my previous games.
Basically it looks as though taking over another good-sized continent is very difficult without a strong technology lead(I've never seen the AI do it). My conjecture is that at Monarch or harder difficulty, you should give up if you find no one to conquer on your initial continent. At Regent level such games are winnable.