Not really being a animator/modeler myself I have to rely on what I can easily learn from the internet. The quickest and, more importantly, cheapest way for me to make models is to use Blender. I mostly just made fairly simple 3D primitives, which works for me until I start getting the engine under enough control that a modeler can just drop complex models in.
Other then the Blender tutorials the most useful page I’ve found is Blender to XNA (fbx) – understanding the model. After configuring the FBX exporter every time I went to export, I finally tweaked the python. This selects just the options I need for the exporter (Scene Objects, Scale: 0.05, Mesh) for this XNA project. It also don’t place any of the producer camera within the final FBX. My “corrected” XNA to FBX script is here.