The good news is, not only is ceramic tile both beautiful and durable, it's also by far the easiest flooring material to clean. Even when it does get dirty, a good washing will generally bring back its shine.
Of course, that doesn't mean you don't have to do a little bit of work. In fact, you should damp mop* your floor at least once a week (more often in heavy traffic areas) with a mixture of 1/4 cup of white vinegar to one gallon of clean water. Slip resistant abrasive glazed tile may require more frequent cleaning, as it tends to capture more dirt.
*THE NOTABLE EXCEPTION TO THIS is right after you've had your new tile installed. Always allow at least 3 days (72 hours) for your new ceramic tile and grout to dry before damp mopping. You may notice a slight film on your new tile from the grout. This can successfully be removed by rubbing with a dry towel or damp mopping after the 3-day drying period.
Protect your tile with mats. To protect your tile for premature wear, you may also want to invest in some good quality entry and exit mats. Mats are also suggested in any spot where you tend to pivot a lot - like in front of a sink or your stove.
Protect your tile from tables and chairs. Any metal, iron, wood or even plastic that will be resting, sliding or rolling on top of your new tile should have an appropriate protective pad such as felt affixed to it. Pay special attention to the chairs you use the most, checkings all casters to make sure that they're in good shape and that no metal will be touching the tile. Metal that touches or rests on the tile can eventually rust - leaving a nasty stain on your new floor, not to mention a bad taste in your mouth.
Say no to sealers and cleaners. Sealers or cleaners for your grout or tile other than white vinegar and water are not recommended and may cause unwarranted damage to your tile, your grout, or both.