Step 2: Source your driftwood
Go down to the beach and collect a bunch of driftwood. I'm lucky enough to live a few miles from the Pacific ocean. I recommend wearing gloves. Most driftwood arrives on our beaches after storms, and other nasty things could be there, too.
Just collect a bunch, anything that has that driftwood-y look to it. You should get a variety, from gnarled tree branches to distressed lumber scraps. For my tree I used 31 pieces. They vary in size from 3 1/2" to 21" in length. They will need to be thick enough to have a hole drilled in them that will fit the dowel. (I first tried a 1/4' dowel, but it was too flimsy. Go 5/16" or larger)
Bring them home and give them a good cleaning in a bleach/water solution. Then leave them outside to dry.
(FYI - this picture was selected for a Jones Soda label. Diet black cherry. Let me know if you find any in a store.)