Wonder Spam

First I'd like to say I'm not the best player. I win on prince and starting King. But in my multiplayers games I play with a few friends(5ish AI) on standard setting prince difficulty.

And they spam wonders.
How do I get around it because I tend to fall behind even using the strategies on this forum.

Also, can someone tell me a criteria for a well-placed city.
such as river, mountain etcetera