Glass will crack if not installed correctly, especially large-format glass. Refer to the Tile Council of North America (TCNA) Handbook for installation requirements specific to your application.

Be sure that the wall has the proper gauged support studs and that they are braced correctly.
Set the appropriate grout joints. Wider grout joints must be used with large format glass tiles. Tiles will crack if the grout joints are not wide enough.
Refrain from putting glass in contact with metal (i.e. faucets, handles, shower frame). Any glass to metal contact will cause the tiles in contact with the metal to crack.
Use the proper adhesive. Different applications require different adhesives. Installers should refer to the TCNA Handbook.
Backs of tiles must be fully covered in adhesive (back-buttered) during installation. Otherwise, tiles will crack.
Level and plumb the wall prior to installing glass. An unlevel surface will create tension across the wall, which will cause tiles to crack.
Installers should always refer to the TCNA Handbook.

Cutting Tiles
Use a standard new, sharp blade suitable for cutting glass tiles, which must be constantly kept wet with water. Cutting the pieces with the colored surface turned upwards and taping both sides will reduce chipping. Cutting must not be carried out near the edges of the individual pieces. Smooth off any sharp edges with sandpaper. Holes can be made with a specific drill bit for glass with a diameter up to 5/16″. Apply water continually while drilling.