I'd suggest taking up Oda Nobunaga (My favourite by far) and committing yourself to a purely military victory. This is quite the hassle, but once you find iron, you're practically unstoppable.

However, another easy victory would be Science. I prefer military however. I once played on an Earth Map: Huge and the military victory was extremely satisfying. I'm currently playing on Earth Huge and have clocked in the custom player number to the max (24) and have placed as many city states as possible. Playing like that is fun. And I do believe the easiest victories in such cases are the Scientific Victories. .... I'd go for military.