[pushkins]

First of all you will need a wet saw, marble will chip horribly if you try to score and snap it. Also get yourself a tile file ($8), so after you have cut it you can clean up the edges.
You will need a good quality tile glue, either a mastic or a mortar based will do, just make sure you get the flexi.....type if your going to use a mortar based product or add flexibond additive.
Most marble tiles nowadays are sealed and at least have a high polished face side, do not leave the tiles wet after cutting, dry them off with a towel.
Hope this helps.