Spin the peacock herls around the thread. (This will make the peacock herl more robust and doesn't require a wire rib to reinforce the herls and hence reduce the weight of the fly which is ideal for smaller hook sizes).
Take a brown cock hackle and catch in where the peacock herls finished. The barb length should be at least the size of the hook gape. I personally prefer 1.5 times. TIP: If you need the fly to sit lower in the water, it is very easy to trim the hackle under the fly.