For a neat hole in such tiles, you should use a glass drill bit. These are good for drilling holes in mirrors, and so on. Their big advantage is that the edge of the hole does not chip, i.e. you get a neat-edged hole. You can use a masonry drill bit, but you might get a bit of chipping around the edge of the hole. If that will be covered by the fitting (wall cabinet, or whatever) the edge chipping does not matter. Your idea of starting with a small-diameter bit, then enlarging is a good one. Use brand new bits if possible.