Often times when you talk to animators, they mainly focus on how good the animation is. They don't particularly care at all about how well the shading/texturing is or how nice the lighting set up is, all that to them is additional bells and whistles that they don't want or have time to think about when animating. While having a fully textured, lit, and rendered shot isn't as important to animators who solely need to show how well they can animate, having a finished piece in a demo reel on top of having great animation can make oneself stand out all the more. There is actually a really easy and fast (both process and rendering) method of getting a "finished" looking shot. This method is similar to what is done for shorts such as Saga of Bjorn, Mac'n'Cheese, and Meet Buck. This is great for animation students or those working on individual projects.
Starting with shading/texture painting. Simply use surface shaders and apply it onto everything with the color that you desire. That's it! One great thing about this method is the versatility. You can be as simple as necessary or go into as much detail as you want. You can use the simple one color surface shader or you can go as far as to detailing the surfaces of objects. If you wish to actually paint the surfaces, unwrapping the UVs will need to be done first. Unwrapping isn't that hard but it's made even easier with tools such as UVLayout or Roadkill where all you have to do is cut the geometry apart, flatten it, then press a button to automatically layout the UVs. As everything is using a surface shader, the rendering time is super fast, a few seconds per frame. Of course you probably want to give your models some form so that everything doesn't look like cutouts on the screen. Render out an occlusion pass. Rendering an occlusion pass will be take the most extensive amount of time to render as it is done through a calculation by Maya of objects between objects. Composite the occlusion layer on top of your diffuse; the simple way would be to use a multiply but a more correct method would be to use it as a mask to drive a color correction. Now you have some volume in the scene and it looks pretty decent. The above looks like it would work decently well, but you this open window and think nit would be great if there was light coming through to create a grid pattern onto the floor. This is really simple to do; create a new render layer in Maya and right click > create material override and apply a basic gray lambert onto everything. Shine your lights in the scene, and render that out. This renders out very fast as everything is just a basic lambert shader. Now composite this light pass on top of your previous image with a multiply adjustment and there you go! In my example, my lights are a bit more extensive as I actually lit the scene with fill and bounce lights instead of just casting a few spotlights for keys.
To get super fancy, if you know what you are doing in Nuke or After Effects, add some bloom highlights, god rays, and a depth blur. Additionally, I took the specular, reflection, and refraction passes from my normal render and composited those in also to get this final look.
Again, this is a quick and dirty way to get a decent looking render for someone, such as an animator, to increase the visual aspect of a short reel piece. For actual texture artists and lighters this would definitely not work as using flat surface shaders means you lose all the actual texture qualities of the material (specular, glossiness, reflections, sub surface just to name a few).