First lesson? Patience, patience, patience… It took a long time for this pinkie-sized eel to stick out its head from the coral. And with every burst of the strobe, he retreated back inside… About 20 minutes of the dive was dedicated to this one picture.  

And never, ever discount luck. This baby squid was one of about a dozen or so mating just feet from the docks at Cayman Island's Sunset House Dive Resort. Its close proximity to the surface also meant I didn't have to rely on a strobe.  

And remember to try to get close. While this shot, taken from about 30 yards, sort of captures the shark's shape, it also caught loads of the dreaded back-scatter.  

Silhouette shots like this one of a coral fan in Belize is one of the easier—and more dramatic—photos to take. Just synch the light meter with the richer blue near the water's surface by half-depressing the shutter button while pointing skyward, than frame your shot.  

Of course, when the light meter fails you, there's always Photoshop. If your photos seem washed out, increase the 'hue' setting (Images > Adjustments) to increase the richness of blue colors, as done in with this photo.  

Up angles create a real sense of drama, especially if you've got the sun shining overhead to add a touch of ethereal light to the equation.  

The use of an external flash let me capture the intricate color patterns of the scales on this angel fish. The camera's own flash wouldn't have provided a quarter of the illumination.  

Truth is, sometimes Photoshop can be your best friend—the original photo was filled with backscatter and weak colors (all my fault). But by manipulating the levels and saturation, I was able to convey the eerie mood this encounter with a Caribbean reef shark in Belize's Blue Hole.