The requirements are really simple, and can be foraged from your catch-all drawer:
Hello Kitty McDonalds Watch (I used the square brown one because it best fits my tastes)
Triangular head screwdriver (you can make your own
! thanks to adrianmonk) or a pair of pliers with a triangular end that will fit into the screw.
Printout of a picture you like (more later)
Keychain mechanism (doesn't matter what type you use, I used a d clip and a plastic clip from my work badge, you could easily recycle an old keychain instead)