A kick-start to model making:
1) Get Magos' War3 Model Editor
2) Do the tutorial for it. (Will teach you basic model editing)
3) Get Oinkerwinkle's Vertex Modify
4) Do the simple and easy tutorials from top to bottom (you'll learn all the stuff in an evening or two)
Oinkerwinkle's Tutorials
You'll learn model editing, scratch modeling (creating stuff from the basic primitives), and UW mapping (fitting a skin to the model).
You can then use these skills with the more versatile MdlVis tool.
For actual model making all you need is
Magos' War3 Model Editor for editing materials, importing textures, making particle emitters, nodes, camera, simple mesh editing, etc
MdlVis for UW mapping, mesh editing, animating, creating new geometry from scratch, assigning vertices to bones, etc
Tip: The primitive shapes that come with Vertex Modify can just as well be used for scratch modeling with MdlVis