I used to be the same as every other diver with a new camera. Shooting like it was a machine gun and deleting or editing in PS for hours trying to recover the shots. Here are a few things I have learned to shooting better shots.
1. Try to get the shot in shallow water with good natural light. The best time for UW photo light is between 10am and 2pm. The opposite for land photography.
2. Use a manual white balance or a red filter for blue water or an orange one for green water and the best results are up to about 12-14m with the correct filter and natural light.
3. In low light conditions for WA shots you have to increase the ISO level. For Macro I found a focus light at deeper depths 20m+ makes for better focusing and shaper shots, non focus light shots were out of focus or to much grain (higher ISO).
4. Plan your dive and your subject. Research the dive site and I find that I get the best shots when I can focus my dive/photo objective on only a few subjects. Eg. I do a dive with a macro lens and only look for shots of Gobies or Blennies and now I do dives where I take no shots at all as I can see when I frame it I will only delete it later.
5. Just because you have a flash in your camera does not mean that you can stay 2m+ back from the subject (on land OK, but not underwater, water absorbs more light the deeper you go plus the camera to subject distance). To achieve the best light you must get as close as possible to the subject. If you think your close, get closer, about 1.5m is max even with a big external strobe like my Ikelite DS-125. Look at most of the magazines and the shots you see are nice and blue but still have color, as they are shot in shallow water down to about 14m ( remember lots of natural light).
6. Take your time, look at the light and the different angles, do you want the subject with a reef background. Or would you like the down/up angle shot to get the fish on a nice blue background and contrast.
7. For a nice blue backgrounds try slower shutter speeds (30-60s) and lower apterture (5.6). For black backgrounds try to shoot the subject against a distant background (eg, blue, or farther than flash distance) with a high F-stop, fast shutter speed.
8. Don't be disapointed as I have met Pro's that have shot 2000 images in one week and kept only 20 shots from the same dive site. I found out that if the Pro's want a shot they will stay in the same dive spot for a week or more. My hit rate is much less
