You do sign your work don’t you? If not, I strongly encourage you to do so (in some inobtrusive place). The simplest way to do this is not with a true signature, but with a symbol that you design. For example, noted metal clay artist Pam East signs her work with the Chinese character for ‘east’ (the direction). My symbol is a bindrune (a combination of two or more runes into a single glyph).
The symbol can go on the back of a pendant, inside a ring, or on the back of one earring or cufflink (if someone owns one member of the pair, they probably own the other).
The simplest way to do this is by inscribing your symbol with a tool (not the pick or needle tool, which might bend, but with something made for this purpose). However, there is another way — place your symbol on the back with a small amount of clay. This is particularly easy with silver — use syringe to place your symbol after everything else is done.
Below is a very simple, very basic pendant and earring set, made of silver clay (texture done with a texture sheet, from done with a template, shaped by drying over a plastic Easter egg, stone [quartz, with inclusions] set in a bezel cup). I am posting it to show how I placed my maker’s mark on the back, with syringe.
The image on the left is the part that shows. The image on the right is the back, with a syringe maker’s mark on the back of the pendant and on one earring.