Usually for SEM you don´t need extensive sample preparation. It is different for TEM, where you have to prepare the sample to make it thin enough for transmission. Anyway, you always can cut your samples by FIB, Focus Ion Beam, but this technique only works for thin samples (at rational cost and time). You also can cut the ceramic with a diamond saw, the same kind you can use to cut glass in a glass blower workshop. If the ceramic is just clay, without enamel you can cut it with a common steel saw and then polish it with sand paper or a file. If you are afraid of contaminations from the cutting or polishing tools, it should be enough to broke the ceramic and choose a piece of the right size to attach to the sample holder. Probably you will need to coat your sample with some conductive layer (Au, Carbon, Ir...) if you want to observe it properly without charge artifacts. If you are interested in elemental analysis, you should avoid the coating.
Thanks a lot for your useful answers. It was quite useful, in fact. Most probable I will try to cut with a diamond saw! It is an excellent idea!!. Thanks you so much.