The most extreme camera operators use a gyro attachment for their camera to get smooth, steady shots. This applies to both still and motion (video) photography. The attachment works by two internal gyroscopes spinning in opposite directions, creating an X-Y stabilization pattern. In an rough, rocky environment (helicopters, boats, Deadliest Catch), the gyroscopic effect holds the camera steady, resulting in a much smoother shot.
You can buy camera gyros from places like Kenyon Laboratories, however such high precision results in a seriously high price tag – they can easily cost over $10k. Or, if you have a couple external hard drives laying around, plus some USB phone chargers and a few scraps of wood, you can assemble your own lightweight gyro assembly following the steps in this great Instructable.
Two things to try:
-Use 2.5″ laptop drives for size (they may not have enough mass to stabilize anything larger than the smallest pocket cameras)
-Putting the drives in-line instead of a 90º offset
UPDATE: BobS, the designer of this gyro system has posted instructions and samples for a much smaller single-drive gyro system – and it looks like it works pretty well.