Steve,
Here are things i consider when shooting and editing...not in any particular order.
Shooting:
-Before i enter the water, what is the purpose of my shoot or what is on my shot list
-Where will i find the subjects i am targeting and what is the best position to capture them in
-What is the appropriate settings and lens for my primary subject (UWA, wide, macro)
-Position of sun light with respect to subject (try to get sun behind me)
-White balance (lots to think of)
-As per Wags, Wide, Med, and Close shots on the subject
-Consider where the subject is entering the shot, allow it to enter and pass, then perhaps follow with pan
-Steady, steady, steady...can't say enough (keep shooting till you get it)
-Provide head room and room to move (position subject in lower 2/3rds and with 1/3rd of frame empty in direction of travel)
-Try to capture subject with appropriate background (pure blue, colorful coral, supporting cast of fish...goal it to enrich the shot without distracting)
-Capture lots of core subjects shots and variety or supporting cast shots
-Capture environment (reefs, caves, bommies, etc) to put the subject in context
-Seek creative perspectives/angles on subject not commonly seen
-Seek unique and intersting interactions (mating, fighting, schooling)
-Capture transition shots (diver bubbles, light off water surface,etc)
-Capture diver shots (entering, descending, ascenting, interacting with subjects)
Editing:
-Throw out all footage that is not technically sound (unstable, poor exposure, not in focus, poorly framed, etc) before i talk myself into keeping it
-Throw out all footage that is not intersting (fish ID type shots, boring, etc)
-Assemble remaining shots by subject (species, location, etc)
-Begin assembling based on storyboard or freeform for fun vids
-Rough cut/trim to desireable lenghts (3 to 10 seconds)
-Assemble according to storyboard
-Throw out redundant clips and clips that don't add to story
-Do this again, and again and again until i am feeling seperation anxiety
-Cut/trim/move to remove jump-cuts (i.e. continue motion from adjactent clips, or little or no motion between clips, or very obvious contrast motion between clips)
-Insert transition shots as appropriate
-Avoid fades as much as possible unless using for effect such as apparent seemless motion of concept melding (most fades/disolves are substitutes for poor cuts)
-Color correction, gamma correction, etc
-Motion graphics and titling
-Music
-Preview, modify, preview, modify, repeat...
-Export