There's not really a right or wrong answer to this question.
It all generally depends on one's ability to socialize and preference when makin' acquaintances. Sometimes friendship can be acquired through role-play (a good place to start here would be in Fluorite Plains where a variety of role-plays are held), sometimes it can be gained through a simple conversation (dependin' on yer comfort zone, ye' can find friendly faces in every public map here though if ye' like locations with a lot goin' on, I'd take a peek in Bonfire Island, Fluorite Plains, or Ficho Tunnels while if ye' prefer more quiet places to just have a casual chat every now and then, I'd look in maps such as South Pole, Temple of Dreams, Cape of Distant Worlds, etc), then some players actually find a majority of friendly faces here on the forums.
Again, it depends on the person. In this case, ye'.
In my opinion the best place to find friends is in the Introduction area in the Forums or character bio's area. Though on the actual game I would suggest Fluorite Plains or maybe Bonfire Island.
The majority of the members hang out in Bonfire or Flourite at two places. Cape Portal and Stone Bridge, in Bonfire the members are everywhere cx Me, well, I hand out in Bonfire, South Pole or Fluorite alot, but I bounce around alot to, so your lucky to find me in any of them c: You can also PM members, which anyone is welcome to PM me for help or to chat, I don't mind XD
~ Whisper