The biggest challenge was creating continuous parallel circuit paths for the positive and negative sides of the LED's in the cramped space on the tree.  The LED's had to be installed in parallel, otherwise they would drop the voltage too low to light up.  To make things easier I printed two copies of the image, one to color for the cover page, and one on which to build the circuit.  I first drew the approximate circuit paths on the circuit-image page.  Then I ran the copper tape along those paths.  As you can see in the image to the right, the paths ended up being very sloppy.  I was concerned that the adhesive side of the tape wouldn't be electrically conductive, so I tried to make "crimp bends" at every turn on a circuit, instead of cutting and overlaying pieces of foil.  They look messy, but they work!  I tested the path with one LED at the top of the tree, and it lit.  The rest of the process was just being sure to keep the polarity of the LED's correct as I placed them in the circuit.

 

On my first test all of the LED's lit up, except for one blue LED.  I worked with that for a while, then tested it across the battery using jumper wires and found it was DOA.  Finally I taped the colored image on top of the circuit paper, trying to line up the LED's with the ornaments and the reindeer's nose as best I could.  They didn't line up perfectly, but the effect works well enough for a first try.