Fish are holding in moderate to slower water, and hugging the bottom.  Focusing on pockets and inside seams can prove very productive.  European style nymphing will be the most productive by providing sensitivity to light takes.  If the water slows down considerably it might be best to throw on an indicator to get a good drift.
With smaller flies, adding weight to your rig is key to getting down deep.  Additional split shot and tungsten putty are necessities this time of year.  Winter time means storms, and lower water levels. Overcast days with some precipitation and light winds will get blue winged olives to hatch by the hundreds.  Look for eddy’s and slower inside bends in the river to collect bugs and feeding trout!