Hi, I've found a "niche" I'd like to target. The main KW has 1.500,000 (local/month). I've found several long-tail KWs in this niche that are less competitive. E.g. 5.000-10.000 local/month (competition: medium). I'd like to place posts for each KW on subdomains and build BLs to them. How difficult are these phrases to rank and what would it take? Thanks!!