I’d say VFX is super technical as well as artistic. I see the VFX guys usually know a lot of everything. So I’d say the first thing to focus on, like any other 3D artist, is modeling. It’s the bedrock of all this stuff, so you can start with the Fundamentals, it’ll take a while, give it time and then move on from there:
https://cgcookie.com/p/core
