Here in Central Texas, we fish almost exclusively for river bass. My key is to locate slack water near a current seam. Downstream from a small set of rapids, downstream from a large rock or log in the water. In or near heavy cover. Bass are like us, they are lazy. They will hold in areas where they can rest from the current, and where the current will bring them dinner. I fish woolly buggers a lot, and fish them on the drift, casting just upstream from such obstructions, drifting past the log or rock. Undercut banks are also good, as are dropoffs after gravel bars in the bends of rivers. Just think about where you would hang out if you were looking for dinner in the river. That' where the bass will be. Good luck.