I need advice on how to improve my game

Hi guys, I have been playing this game for some time and I just can't seem to further improve my game. Until now I still have no idea how to beat an extreme AI. I usually main British but I've been practicing Chinese, Ottoman and Japanese recently. I know all the basics about settlers, exploring and home city etc, but I seem to find that my problem is I don't know how to manage resources in Commerce Age that will allow me to rush the AI, let alone human players. Can any veteran players give me some advice on how to do rushing?