Really depends on the type of river your fishing. The faster shallow & more natural rivers can be easier to work out where a good plsce to start is . As you might have a field or two of shallow fast moving water which then slows & deepens for a bit , always a good place to start for any specimen river fish where it first deepens after a shallow run , also on these rivers quite often there will only be one possible route for big fish to use in the shallower sections again another good place to set traps.
On the deep slow coloured rivers it can be tricky like your finding spotting fish day to day , you might get lucky & one crashed out while on a wonder or you get to spot a couple in the margins but in my experience that's not that common , so it's more about picking somewhere out the way features or not & start baiting if there in the area there get on it . But wier pools old snags overhanging trees, undercut banks etc are all worth a bit of bait .
At work now so got to log out