Before removing even one tile, you need to remove fixtures or cabinetry that covers any tile, such as the toilet, sink, etc. Remember to turn off the water supplies to said fixtures before removal. This gives you room to both remove the old tile correctly and install the new tile.
Choose a tile in the center of the floor or wall and use a grout removal tool to scrape out the grout around it. To make the work easier, first use a grout saw to make an initial cut in the grout lines. Drag the grout removal tool along the grout line on each side of the tile to break up the grout. You can use a hammer and chisel to chip away at the grout to remove it as well.
Wear safety glasses to protect your eyes from flying debris and dust, and wear heavy gloves to protect your hands.
When working on floor tiles, you may be on your hands and knees frequently. Wear knee pads to protect your knees and to remain comfortable during the job.
Cover the tub and any other surfaces with canvas drop cloths to protect it from grout and tile debris and accidental damage.
Once the grout has been removed, use your chisel, metal putty knife or similar tool to slide under the edge of the tile and pry it up from the surface below. Continue to remove grout and pry up the tiles in this fashion.
If removing tile from a large floor space, use a pole-mounted scraper or a long pry bar to pry up the old tile quicker and easier.
Place the broken tile pieces in a bucket for disposal. When all tile and grout has been removed, sweep up all debris and discard of it. Use a shop vacuum to ensure you’ve removed all dust and debris.