is there a trick to decorate a christmas tree?

lights first, and more of them than you think you need. wind them in and out along each branch towards the trunk instead of wrapping round the outside - that's what makes it glow from the inside rather than looking like a lit cone. then garland or ribbon, then the big baubles tucked deeper in to fill the gaps, and the small ones out on the tips. topper last, and step back across the room every few minutes.