i dont know if someone here start a tutorial about maya or max or blender will really help at the end. and maybe its not necessary. But if its good and educated why not
tutorials of modelling tools from basic to advanced and expert are thousands in the web.
But if i can help ill tell you that. The first thing to do is to choose your 3d modelling tool.
I choose blender cause its free of course but its powerfull enough to fullfill most (if not all) of my needs.
i really cant do a proper tutorial cause my english speech is at very low level and maybe that will be more destructive than creative.
so ill tell you what i did and i still do. first of all watch many tutorials. youtube and vimeo are full of blender tuts.
if your sprites are objects (terrains,houses,fences,cars or any object you want) its simple due time and learning via tutorials to model
if your sprites are animated (from humanoid,robots to seas, fires, cars,mechanisms and tornados) you have to first learn how to do it again via tutorials and there are plenty and then the whole process is very easy.
you render every frame of the animation save it as .png if you want transparency (most of time), or as .jpeg.
if you animate lets say a human to run and the animation lasts 30 frames you have to render 30 different images and import it to c2 only for "run" animation (at the process of rendering in blender i choose sampled motion blur on because it smooths the change between frames better) and last but not least the more frames the more smooth result you will get and more ram usage of course...