There are some really good online tutorials. Go to the Canon learning center and search for 5D MK III. Of course, you will have some issues, so after each time you use the camera, review images with a eye as to how to improve the image next time.
First order of business, AFMA your lenses. You cannot get sharp images if you are front or rear focused.
I stick to a high shutter speed at first, and let the ISO rise. This helps get sharp images, and noise is not much of a issue even at ISO 3200.
Once I am getting good and sharp images, then I start to experiment with other settings. It only took me 200 images or so, coming from the 5D MK II and 7D, and my images were lookiing pretty good.