I was tiling all day today and was shown a great way to do this recently -
although you need a wet saw. Draw a curved line on the tile where you
want
to cut it. Then make several parallel straight cuts with the wet saw,
going
from the edge of the tile as far as your curved line. These cuts should
be
roughly a quarter-inch apart. Use the nippers then to break these thin
pieces of tile off. I assume you can do the same with any saw that can
cut
straight lines in tile but the wet saw for me today made the work quick
and
easy. I had to cut four tiles to fit around the toilet flange. If your
tiles are laid out so that one tile fits over the flange, cut it in half
first, then cut two semi circles using the method I mentioned.

Good luck!

I'll try this. I bought a wet saw as the bathroom was the first of three
rooms I plan on tiling. The flange hole is covered by one tile though a bit
off center. If I cut the lines close together on each half inside the
semicircle I can see where I would be able to nip the shards off without
breaking the rest of the tile. Thanks a ton.