A word of advice: I found Blender really hard to understand (I think they based it on GIMP :).) Something that helped a lot was figuring out how 3D graphics work first. Specifically vertices, faces, and meshes, then coordinate systems, vectors, and transforms, then lighting and cameras, and lastly textures and UV coordinates. I did that using three.js to display things in a browser with a bit of javascript. Once I'd figured that out and had a much better understanding of what 3D engines actually do I found it a lot easier to work out how Blender lets you control those things in it's interface.
I'd really love to play around with three.js to pick up some of these ideas. Any suggestions on the best way to approach teaching myself those concepts?