ronscuba makes an excellent point. Best thing you can do is make baby steps.
In my personal experience of filming in and out of water those are 2 completely different schools of thought. What works on land does not work in water and what works in water can not be applied to land.
Perfect example:
My mountain biking videos (shameless self promotion plug click on my signature hehehe) we all filmed in a period of about 1 month riding trails over and over and over, setting up cameras, riding over and over, moving cameras, setting up, riding etc etc. And then I started researching what makes mountain biking videos successful... as in why does 1 video generate 1.7 million views in a day and another gets 3 views in 6 years. I learned what I need to leave at editing table and what sparks interest. I learned that people's attention span is short (at least on youtube) so making videos longer than 3-5-10 minutes is a career suicide. I learned that humidity, sun, shade, weather and all that stuff play a huge role.
Same exact could be said about scuba videos. When I first started filming in 2008 my videos looked horrible. Camera shaking all over the place, constantly missing the thing I was trying to film, having all kinds of buoyancy issues because of camera. Editing was even worse until after about 2 years I ironed out all the kinks through baby steps.
As for professional videography I would say that #1 you need to be proficient in baby steps before even trying anything more challenging. After you master what you learn only then can you take additional coursework. Coursework will teach you a few more tips and tricks but editing is where it makes or breaks the ice. You need to be brutal with what you leave out and even more so with what you keep. You can learn all of that by challenging yourself and learning from others.
I learned to do what I do by filming a blue tang for example then realizing that my video totally sucked. Then I would attempt to capture blue tang in a better way and improve etc etc.
I would say as a videographer learn fish behavior, learn how to position shots (ie not filming into sun), learn to hold your camera without shaking it. In my case I love to let fish come to me. I do not chase them too much, I just hover and they get comfortable and I can shoot without scaring them or anything. I was filming this puffer (in one of my videos hehehe another shameless plug) for about 20 minutes just because he let me. I am all puffered out after that which is a good thing because now I will probably learn to skip certain types of fish that I have gigabytes upon gigabytes of footage of. My hard drives contain about 640gb of scuba stuff ie folder for angels, folder for trumpet fish etc etc.
---------- Post added February 4th, 2013 at 11:25 PM ----------
Here is an example of a well put together video. Not my own but of some high school aged kids at Weeki Wachee state park here in Florida Canoeing. You can watch 300 canoe videos and only see one that looks like this:
It tells a story that starts at parking lot and ends at upside down boats, some diving, some crashing, splashing, cool angled shots, sped up and slowed down footage. I guess it has one of everything in it.
https://www.youtube.com/watch?v=QZvLvu2OxrI