One of the things that I noticed last night when I was attempting to build a new city was that  had no idea how far away I needed to be in order to build a new city.  It just kept on telling me "you are too close to a settlement" until I eventually reached the happiness zone where I could build a new city.

Suggestion:  When the dialogue pops up for the too close message, how about highlighting the squares that are buildable in green or something?  Having to find it by trial an error is kind of silly.

Thanks,

Ishantil