I'll organise this list into necessities, and handy items.
3 or more old loyalty cards, or hotel room keys, or false credit cards that come in the post, etc. (the stiffer the better.)
Super glue to stick the cards together (plastic glue or duck tape might work.)
* A Gorillapod
with a sticky-back clip
or something else to mount the cradle on (A wooden or wire frame was the next thing that came to my mind.)
* The device you want to make the cradle for (You need this to shape the cradle correctly.)
* A permanent marker (a ballpoint pen or soft pencil is the next best thing.)
* Duck tape.
* Any leads you may want to connect to the device (Chargers, sync cables, etc.)
* A file or sandpaper.
* A ruler.