This time of year tie yourself some grey scuds (14,16,18), various color zebra midges, micro-egg patterns (18 or so), BWO (18,20,22), cream and black surface midges (22, 24), and san juan worms.
For Nymphing: If fishing a low and clear day, use the eggs and zebra midges, normal days use egg and scud, and wet/post rain days use scud and san juan worm. Also think about tying some walts worms in all colors.
Limmit your surface casts to only when you see consistant rises, too many people waste their time with dry's and picky browns at valley, so mainly stick to nymphing (this time of year at least). If your gonna go up top, use light lines, long leaders, and be stealthy.
In general the fish are pretty spooky there, so try to work on 1 or no false casts, and side-arm casting to not spook them with the movement of your rod-tip.
These are just the methods I used and they worked for me. There are many other ways to catch fish there, so just pick and choose from all these posts what works for you so you can develop your own unique style to approching the stream.
Tight lines...