After the lights: garland
There are no firm rules when draping garlands on a tree (as long as you don't create a sausage effect, with branches bulging between tightly-cinched garlands).
Start at the top, stringing less garland, and work your way down, increasing the amount of garland.
Thin bead garlands look best swagged from branch to branch; thick paper, ribbon, or foil garlands look best wrapped loosely around the entire tree.
BH & G experts say to use a variety of garlands -- from plain to fancy -- to avoid a busy look. For every vertical foot of tree, use about two strands of garland.
However, I never opt for less when more is an option. My Victorian tree is dripping with bead garland. I used every strand of gold and pearls that I have.