1 thing, spend as much time texturing as yu would modeling,
a few ways yu could do this, with uv map, what i do is, use the material editor and create basic colours to make a basic note of what colours the polys should be then I texture bake the model(flatten mapping) and that should give me a basic "outline" texture for the model without the need to grab certain points and mumbo jumbo texturing, use the baked texture and add detail like yu normally would(and prolly resave the new texture)...then delete the baked texture map(or whatever its called) from yur modifier stack list and also remove the texture bake from yur material editor if it has automatically created one, if yu don't yur model/viewport texture looks ugly. then stick in yur new texture in the material editor and apply it to yur model, it'll be back to its default mapping so create a uv map in yur modifier stack list and change mapping style to flatten mapping and have the same settings as when yu have texture baking, the polys should be in the same co-ords as the baked co-ords.
neway, thats just how i do it, theres many other ways, best to just do whatever suits yu best
