Torrey's excellent post about overall strategy during high water conditions had me thinking about river structure. I thought of a few additional comments that pertain to all conditions, but especially to high and dirty water. None of these recommendations are exhaustive or absolute.

These suggestions may help you maximize your time on the stream, and allow to bypass some unproductive water. It also pays to watch where fish rise during a hatch. Before and after the hatch, fish those same areas with your nymphs. In general, you should read the water and look for:

(1) Current seams, especially around boulders or fallen trees. With respect to boulders, I think many people assume that fish will be sitting directly behind them. That can be true, but I have found that area of flow can be turbulent, and fish don't like turbulence. It is usually better to fish some distance behind the boulder.
(2) Inside bends. Say you're on a river bank and the river flow is left to right. Looking downstream, if the river curves towards you (to the right), you may have found an inside bend. The soft water along the seam of an inside bend can be deadly during high water.
(3) Undercut banks. Fish them from the shore if you can, or take the time to walk well around the area and cast to them. Anywhere you see any kind of tree roots above the water might be good.
(4) Stream confluences. Anywhere two currents join, there will be soft water right above their junction.
(5) Directly above the entrance of a tributary, especially if the trib flow has gouged out a bottom depression.
(6) Any kind of a trough or depression in the river bottom. These can be hard to find and they shift with erosion, but they often produce. Quite often when you wade you will find a deep hole; mark that spot for the next time you fish.
(7) Any distinct change in color on the river bottom. My favorite is clean sand alongside some gravel and small boulders. I think that fish perceive the color contrast as a lengthwise place for them to hide, like a tree.

Areas to avoid:
(1) Turbulence
(2) Back eddies
(3) Extremely long stretches of river with no change in composition. Remember that different food items have different habitat needs, so a diversity of composition (riffle, run, pool) means diversity of food and more likely feeding fish.

Perhaps on my next trip out, I will try to photograph these types of structures.

At one time, there was also interest on this board about a "Reading the Water" class. If there is still interest, maybe we could arrange something, let me know.