I was wondering if there was any way of knowing that a certain tile among the concentration of the same resource will be a naming tile, such as knowing that the outermost resource or something will be it. Also, is there a trick for rivers, such as walking across it at the coast. Finally, how many resources must there be together to even get you a naming tile? In my experience it seems random, but I'm not sure so I'm asking if anyone wants to shed some light on this for me.

Thanks.