I moved and hid copies of the original and revealed certain parts so the particles of the cat looked spread out of the original.
Making Vampire Teeth
I selected the incisors and warped a copy of them until they looked sharp like vampire teeth.
Changing Hair Color
I used a soft light brush and eraser on a separate layer to create an overlay of color.
Changing Eye Color
I selected the iris with the pen tool and edited the hue and saturation until I found what looked good and looked realistic.