The wiki will help quite a bit, once you've gone over those tutorials a few times I'd try going through a few different gamemodes to see how they do certain things.
http://www.lua.org/pilThat's a great resource, and helped me out quite a bit. You can also buy, or download..., the second edition. I downloaded a copy and it's great. The wiki is a great tool for GLua functions, hooks, and other stuff that only GLua uses. You can also look around in other people's work like gamemodes, addons, or just small code snippets.