The digital medium really has its advantages to helping the artist look at the work as a whole and to catch composition and anatomy issues on the fly. I can flip or rotate the canvas much more conveniently, which helped on areas such as the face (it is easier to paint a face that is upright as opposed to almost upside-down) and keeping the composition balanced (this came in handy for making sure the fish were arranged in a dynamic, but aesthetically pleasing fashion). I was able to get a "fresh eye" more often and I think that helped my work dramatically.
Another way I took advantage of the digital medium was to note the percentage I was zoomed in and keep that constant in areas of the similar focal "importance" as I rendered details. Up until I put in the details, I was working at no more than about 30%. In the final rendering stages, I allowed myself to zoom in to 100% for the face, but everything else, I was probably between 50-70%. This helped me emphasize the focal point and keep areas of secondary importance looser and less detailed. In the past, I was not very consistent with keeping myself a good distance from my canvas. I can see how the digital medium could be even more tempting, but for me, as long as I kept track of my zoom percentage, I was golden.
A summary of things I learned:
-Don't crop your focal point. Note the awkwardness of the cropped head.
-Less is more, as usual. I was going to give all of my fishes the detailed outlines, even the distant ones. Making solid silhouettes was not just more effective to describe the "atmospheric" effect of the murky water, it was also less time-consuming.
-Beware of tangents. You can see a tangent formed by nearly parallel edges of the hand above the water and the edge of the ship.
-Photo reference is your friend. I used one little fish maquette as reference for a billion different fish. One unexpected, but pleasant consequence of using my own reference was preserving my "style". I don't like to use that word too often, but not only shooting your own photos, but making your own sculpted maquettes can enhance the character and cohesiveness of your work.
-Google Sketchup is an amazing resource, especially if you are like me and have little experience drawing anything of a mechanical nature. I used a free model yacht that I just rotated to the right angle to use as reference.
-Color, not just value, has the power of bringing out silhouettes. I had another color scheme in mind before I found that putting my color opposite (orange) behind the blue body really helped define the silhouette.