+1 for The Five C’s- it is an invaluable resource. Also, you probably already know this, but storyboarding can help you with ideas before you are on set, so if, for example, you know that you want an establishing shot of your environment, a master of your cast interacting and which close-ups you plan to use, you can plan your coverage to match the natural light most closely (continuity can be a pain when shooting outdoors).
Also, you will probably need to supplement the light around, so don’t forget some bounce boards (even foam core is fine for this) and some reflectors. Remember to white balance your camera to the environment.
Finally, sound is a major factor- no matter how ‘pro’ something may look, folks will generally give more of a chance to anything with good sound capture.