The mentor system works quite well on Iwaku from what I’ve seen, but everyone I know have opted out of it – but that comes with being veterans coming to a new site opposed to being new to the artform. I think its a good idea, but it takes a bit of commitment. 

I would recommend pinning or just contributing to major discussion thread (such as my music thread or the general politics thread) to promote actual discussion as well as rudimentary forum games. Perhaps some strategies to get newcomers involved in discussions could be beneficial – we have a few of these in RP discussion (where did you start role-playing, etc).