The only regret that I have with making this costume is that I didn't use interfacing on the back of the leaves to make them stiffer. Interfacing is pretty cheap and you can get fusible stuff that sticks to the fabric with some ironing.
FYI - Like any piece of dog clothing, supervise your dog when it is wearing this costume. Before you go out on Halloween with your dog, practice wearing the costume and walking with it on. That way you'll BOTH have a fun Halloween!