Here's a photo of my version of the X-mas tree...


It's tied with a size 6 TMC 2499SP hook (short shank, wide gape, straight eye) and metal bead. The wing material is Polar Flash - silver. You can use a variety of material including flashabou, krystal flash, angel hair, etc. I don't use anything else (i.e. the bare wire hook acts as the body!).
Anyway, tie in the polar flash first. The material should extend over the eye of the hook and will be wrapped back over the bead later. Trim the excess and whip finish. Cut the thread off. Next, add the bead - with the big hole facing forwards. This will allow the bead to slide over the secured portion of the wing material. Slide the bead up nice and snug and tie in a good thread base to prevent the bead from slipping back. Consider adding head cement or substitute to the thread to add extra durability. Next, pull the wing material back over the bead and secure directly behind the bead. Secure the material in by building up with thread wraps. Whip finish. Cut the wing at the rear to the desired length. I like to angle the scissors when I do this to create a tapered end. Next, add head cement or substitute over the thread and wing material over the bead. This will significantly increase this fly's durability.