Clay pots-preps before mosaicing?

Hello everyone,
A few years back I did some mosaics, mainly wall pieces, flat.
I avoided working on clay pots for the simple reason of WATER and ELEMENTS.
Please tell me, in plain English, and without giving names of brands (I am in Romania and stuff available in the US, can't be found here, or it has different names/brands).
What do I need to do before I can mosaic a clay pot.
It will be ordinary clay pots, with a hole in the bottom for drainage, and a saucer (won't be mosaicing it though) and probably I will grow succulents like Agave and Aloe (you know, they don't require a lot of water) and finally even sell some.
Thank you!

Oh, here's a link to all my mosaics :)
http://entertainment.webshots.com/album/578511476MqLIpx

Calin