Using the 1 mm wire make a star shape and tie off once you are happy with the size and shape. 

Taking your 0.5 mm wire wrapp a small piece around the edge of your star shape and secure into place, cut the wire roughly and arms length so it is manageable to work with and star threading a small amount of your chosen coloured seed beads onto the wire. stretch the beaded wire across to another side of the star and wrap twice securing the beads on this strand of wire. You want a slight curve so the star is 3D and this needs to repeated until you are happy with how many beads you have on your decoration and until the star is 3D like. 

On one of the star points, Attach three jump rings to that point and then thread some Monofilament Illusion Cord creating a loop for hanging on your tree.