Well, we saw this coming, now we just received confirmation, of new Poke Stops being added into Pokemon Go. Although these reports have been conflicting in nature, but at least on the bright side, we have seen results in less than 7 days, which is pretty damn awesome.
Most of these new Poke Stops additions have been done in places, where Ingress agent activity is high. It seems that most of the portal submissions requests are being reviewed on a daily basis.
Simply put, If you need more Poke Stops in particular areas then the only condition think that you will be needing is that you will be needing decent to high Ingress activity to review new portal submissions.