I am developing a game, but as I am working on it alone, the amount of content I can create is very limited. Because of that I want my game to be modded, for this purpose I am planning to create a complete modding API which would be exposed for lua scripting. I would also create tutorials to get people started. And the "Original" game would also be a "mod"(similar to Warcraft III maps) .
My question is: What can a developer do to encourage modding of its game?
PS: my game is a sandbox-ish multiplayer survival(most things are procedural).