I had a some carbon fibre lying around so cut out a quick template I can use with my moleskine diaries. It took about 20 minutes and the waste cut-outs were up-cycled to key rings, bookmarks, and bag tags.

Materials:
- A5 sheet of something reasonably solid (I used a 0.5mm thick carbon fibre sheet but only because it was spare).
- Sandpaper

Tools:
- Dremel
- (optional) Drill

Caution:
If you are cutting carbon fibre make sure you wear goggles, a proper dust mask, and gloves. It throws up a lot of nasty dust and splinters, which can be very sharp.

Step 1: Make Template

Sketch yourself out the template you'd like to cut. Leave at least a 5mm border, more if you are a little shaky with the Dremel, less if you are feeling cocky. Attached is the template I used which will fit a standard large (13cm x 21cm) moleskine. Stick it to your material. Try to align it with the corner to save yourself a couple of cuts.

Moleskine template.pdf
Download

Step 2: Trim and Sand

Carefully cut out all of the blocks. Try to be reasonably accurate so you can use the cut-out portions. Don't worry if you overshoot a couple of edges - if you've selected a stiff enough material it should still be pretty solid.

Sand around the edges and corners. Give it a thorough going-over as you want to ensure all carbon fibre splinters are gone - they are super sharp. Sand the outside corners down as well.

Finally the cut-out portions should be big enough to be useful - I made myself a key ring, 2x bookmarks, and 3 x bag tags (with corner holes drilled for ties). Just make sure you give them all a good sanding and take the corners off. Enjoy!