If this is your first time, you might want to be on the safe side: Buy a little more tile than you think you'll need. (If you don't wind up using it, you can frame the extra tiles with wood and turn them into coasters or trivets that match the decor.)
First, let's look at the best method of score-and-snap tile cutting, the easiest and fastest way to handle straight cuts. Mark the cut on the tile, of course. Then place it in the cutter, and -- depending on the model -- push or pull the blade over the tile.
People run into problems with tile cutters when the cuts become erratic, leading to uneven edges and chipped tile. You can prevent this in a few ways. First, check the alignment of the cutter periodically. Second, use a paintbrush to run a line of light oil along your planned cut -- that will help the blade score the tile smoothly [source: Byrne]. Just remember that the oil can keep your adhesive from sticking, so wipe off all the tiles before setting them.
To make L-cuts or diagonals, you'll need to use a wet saw. Mark the planned cut on the tile carefully with a ruler and a grease pencil. The saw has a guide called a rip fence, which helps you measure and straighten your cut. See the scales at each end? Use them to help you align the tile.
Now that you've aligned the tile with the rip fence, turn on the saw. Guide the tile gently and carefully toward the blade. Don't push hard, and don't keep moving the tile once the blade has cleared it. After you've made the cut, turn off the saw and take the tile out.
Take a look at the cut you've made. Is it clean? Great. If there are chips, you can smooth the cut out with a second pass from the saw.
One DIY expert notes that you may see some light scorch marks on the cut edge of the tile. (Even a wet saw creates a lot of friction when it passes through porcelain.) Fortunately, grout usually covers that sort of scar [source: Staggs].
As you might imagine, if a blade can leave burn marks even when it's passing through a cooling pan of water, it's traveling pretty fast, and that can be dangerous. Don't even think of starting your project before you've read the next page, where we look at safety tips for cutting porcelain.