Bookmark design ideas
If you choose the size 5 x 21 cm, you can design a ruler on your bookmark's back side. This solution makes your bookmark even more practical.
You can also turn your bookmark into a handy calendar , since on the back you can layout the 12 months of the year.
You can also layout a cooking recipe. In such a case, the bookmark would be ideal to go together with a book on culinary topics... (not only cookbooks, but also food-related titles).
Depending on your professional activity, you can design your bookmark according to the products or services you offer. It's just a matter of letting your imagination run free.