Setting tile floors most always requires trimming to fit around door frames, along walls or to accommodate other fixtures in the room. With respect to doors, you may take two approaches. You can trim the door moulding to fit the tile or trim the tile to fit the door moulding. The first method may still require cutting tiles but with less precision. The second method results in a precise fit to the door frame. The choice depends on what tools you have available, the look you prefer and the time you wish to devote.
Place a tile on the floor next to the door jamb. The tile will establish the correct height for trimming.
Remove enough of the door jamb's moulding so the tile can slip underneath. With a backsaw against the tile as a guide, saw the moulding. Do not cut into the framing studs behind the moulding.
Slip the tile under the moulding to determine whether you will need to trim the tile around the framing studs. Mark any cuts you need to make using a marking pen.
Put on a pair of safety goggles and line the tile up on the wet saw mitre gauge. Turn on the saw and make a series of parallel cuts to the stop line you drew on the tile. Turn the saw off and remove the waste pieces between cuts using a pair of tile nippers.
Copy the door moulding profile with a template gauge, a tool that consists of a series of metal rods which can accurately conform to curves and details. Template gauges are readily available at home centres and hardware stores.
Line up the tile to determine where it will meet the door jamb moulding. Trace the profile onto the tile with a marker using the template gauge as a guide.
Cut a series of parallel lines into the tile using a wet saw. Stop the cuts about 1/8 inch short of the profile outline. Remove the waste between the cuts using a pair of tile nippers.
Trim the tile to the profile outline by grinding the material with a carbide grit sander. Use gentle pressure. The tile should fit up against the moulding, fitting the profile precisely.