This question came up recently on a forum, and I posted this quick pictorial. Everyone does it differently, and its best to find what works well for you. This way you'll get a more sparse throat, but you can just as easily leave on all the hackle fibers on both sides, fold the hackle, and tie it in the same way for a fuller throat.
Start with your feather, in this case a Hebert Hen hackle
Pull back the fibers from the tip, leaving some intact
Strip the fibers from the left side, and all the fluff from the bottom
Tie it in thus
I made 5 wraps of the hackle - these have thin stems
Fold the hackles evenly down each side and take a few wraps back to secure them
I often find some of the fibers from the very top of the shank do not tie down well, so i just snip them off
This method works equally well for rooster hackles too.