Imperial Age Strategy

I have been playing DE like a mad man, and I have been wining most of my games. However, I have found that most of the games that I play past the 30 minute mark, I lose.

When you play, what are the strategies that you usually like to go for in imperial? I'm aware that there is a vast amount of strategy at that age, but I need some inspiration.

Also, if you have had this problem, I would love to hear how you've fixed it.