I've had really good luck DMing people to become friends, and then turning those friends into players when I was ready to hatch my idea.

I looked all over the place for people with Danganronpa avatars and just struck up conversations with them. After a few week or so of chatting, I let them know I was making a Danganronpa RP and got feedback from them. I involved them in all kinds of aspects from what they thought the rules for character creation should be as well as just discussed concepts for the RP. As an example, Danganronpa takes place in a secluded location where a murder game can unfold, so I would tell them about how I could overcome that to let new roleplayers join down the road. It worked very well, and 4 years later one of the people I approached this way is still playing. 

But it sounds like you've already made your RP. And while people genuinely enjoy forging new friendships, they don't like to be sold something. I would just do a periodic status bar avert. it's the difference between seeing a flyer in the mall and getting spam mail. One gives you a sense of discovery and can be ignored easily, the other can be a bit of a nuisance.