Im currently playing my first emperor game (standard, all vics, iroquois) and I went granary first. I focused my first few cities towards the AI to build some borders, then filled in the inside with tight cities about CxxC. At the end of the REX I had about the same amount of land as the AI, maybe slightly more than some of them, yet I had probably double the number of cities due to the AI's wide city placement. I think that is one of the things a human player needs to take advantage of. Build the wide placement like the AI, but then fill it in with tighter cities so you can surpass them in production.