Clearwater River steelhead flies can range from very small sparse wet flies to big bushy dries and even large Intruder type patterns in the Winter. Most people prefer somewhere around a size 6. Green Butt Skunks, Lady Carolines, and Purple Peril's are all good starting points. Generally sizes will be 2-4-6 but also bring some smaller 8 and 10's. Some of our favorites are below.
And here is an amazing Step by Step tutorial of the Lady Caroline by our friend Stuart Foxall.