You should know the measurements of the space to be tiled and the measurements of the tile that you plan to buy. Before installing tile you will need to repair any cracks, bumps or dips. You should remove any trim around the floor. And, if doing a bathroom remove the toilet. Good things to know before installing floor tile would be how long the floor will take to set, as well as if you have all the necessary tools to complete the job. Most floor tile installs will require some tiles to be cut, so make sure you can measure and cut the tiles as needed. The installation of the tiles will depend on the instructions listed on the tiles you have picked out so make sure you read these carefully before starting.