I disagree with Kid R, actually. Early gems are really nice, no question about it. However, unless you're trying to do something tricky (very fast Horse Archers or shooting the moon with the Oracle) I would rather have the gems a little later.
Food, like your corn next to a river, is much more important for your first tile, and production/ food is best for the next four tiles (cow on the plains and the two hills are excellent). As an aside, since you "only" have four nice tiles of that sort, you should probably not let your city grow past size four. Build workers and settlers non-stop a this point.
The reason is that settlers and workers are expensive but pay off way better than anything you can else you can build at the beginning of the game. Getting your cities to grow quickly is also very nice.