Okay, a few tips first:
-When you finish, make sure there are no other lines shown. As in, no dog, no signatures, no shadows, etc.
-Also make sure the background is transparent.
-Adjust lines to match the MLC. If the dog has a folded ear, adjust the hat so it fits. If it has wings, erase the confetti in that area.
-Tweak them however you want. (i.e., a puffball on the hat)
-It doesn't matter if the accessory isn't in quite the right spot, I can move it around in Gimp.