I've layed down lots of Granite ,slate and ceramic over the years,like everyone else has said ,rent a wet saw, start in the middle,try a dry run just lay out the tiles on the floor and consider laying them like this
This is what i did in my Bathroom,the tile is Indian multi slate and i layed it this way to hide that fact that the room is 4 inches out of square along the long wall :roll: nice framing boys.
thats the best way to hide a room thats out of square and although there's more cuts its the easiest way for a newbie to install a professional looking job