Try both upstream and across and down , try and keep the lure as close to the bottom and as slow as possible, (just enough to get the lure working). Cover every inch of likely pools, don,t be in a rush, take your time, braid helps show the sometimes very delicate little bumps and nudges, if in doubt, strike, if you get an enquiry, but no hook up, change to a different size/colour lure, cover the fish again, change the angle/speed, be prepared to lose hair as you pull it out in frustration. Salmon can show an amazzing ability to follow and mouth a lure without you feeling very much at all, if the water is clear, polaroids are essential, watch the lure, if it should just disappear, strike, you never know. Fish will very often just follow but not take, time and time again, just move on and try again later!
good luck and happy hunting,
Peter