Start with some bendy stems (dogwood, willow or hazel) and form a circle. Then wire in yew branches to form the base, winding the wire round and round (ie use a continual length). Carry on with the second layer of holly (this year is a berry-ful year). This is then sturdy enough to poke the finishing touches through - I used pittosporum, twigs, cones, limes and chillis....
