Hey Jim
If you find the secret to making $s on u/w pics would you mind sending me a PM - and don't post the answer 
There are doubtless Wetpixlers who do make money - and a living - out of their photography. But it isn't easy. I make a bit having built a collection of stock images which are with agencies. But it's a case of making micro amounts through the sale of lots of images or making a larger amount occasionally. It may sometimes pay the electric bill for the monitor. The reward, for me, comes in seeing the pics sell and the pleasure of knowing that others see value in them. (so thanks for the comment on my pics. Appreciated).
Others may contradict me, but I often think many here make money out of their involvement in u/w photog rather than necessarily picture sales. For example out of teaching u/w photog and running courses - and often through getting reductions in, say, dive accommodation or reduced/free liveaboard rates for bringing a group along. I ran a dive resort in the Lembeh Straits for a while and met quite a few people who travelled the world doing u/w pics and writing articles for magazines which paid very little, but the resorts and dive operations offered them a greatly reduced rate for a bit of publicity. So they did loads of diving, got lots of pics and sort of lived on the road at reduced prices. Tough way to make a living though.
If I am on a trip somewhere I try to do a photo slideshow (with apologies to those who have been on the receiving end!) as a way of highlighting my pics and encouraging interest. This works sometimes and I have sold large, framed prints to a few people. But the oohs, aahs and wows, great to get though they really are, don't often translate into sales!
As for your question on telling a story, I'm sure if you Google around on composition and photo story telling you'll find all sorts of info. Some of the strongest story telling images in my mind come from the Vietnam era. Check out the images, for example, of Don McCullin. Really powerful story telling. I'm not sure if its the changing times (or me getting into old geezerdom) but the number of people producing such images seems to have dropped. Maybe its a result of the ubiquitousness of photography as a result of digital and the iPhone and now GoPro. Everyone has a camera, everyone takes pics/video and everyone posts it. For free. The result has been a drop in the value of images and a reduction in the ability to earn a living from them for other than a very small few.
Which brings us neatly back to where we started.... what indeed is the secret?
I wish you luck....