You just stay around, try to contribute with quality content, then hopefully (or not) it will reach critical mass. One of the things I am starting to like about here is that it's so small, you already replied two of my comments in two different communities.
Although to be truthful, the only real migration was from Digg to Reddit. Orkut never caught up, and moving from Digg to Reddit was easy, at that time some posts on Digg were about complaining that Digg's that day frontpage was reddit's yesterdays frontpage. Moving out was simple, a slightly bigger community than here. Ss we are so few, we need to bring the content ourselves. Just post about what you like and eventually it will become bigger, like reddit (it wasn't what it is today, in some sense, here feels like that original reddit 7-8 years ago) I am trying to lure some redditors from r/Zennonet and r/Quest?, people in there are already willing to jump of the boat, they just need an incentive.