In this method you will need a bucket of water that goes up to your elbow, you will need gloves, rubbing alcohol, string and a lighter. Rub the string in the alcohol and then tie it around the piece of the glass you are intending on making the cut. This must be done tightly and will not be successful if it is not. Once the string is tied tightly, light it on fire, once the whole string is on fire, pick up the piece of glass and plunge it in the water. Hit it on the point where you want to break it off, this lessens the vibration so then it will only break at that point.
You will still need water in this process, except this will have to be laid down on a tray in the water, this must be submerged at a depth of 8cm. Start with a clean piece of glass and make a thin cut with a sharp tool around the glass, make sure the wire is longer thank the cut because you will need extra wire for handles (wood is recommended). Heat the wire till its red hot, when it is, place over glass and then put into the water, the heat of the wire against the light cut should let it cut at its own accord.
When working with glass there are a few recommendations, try work on a table that is stable and roughly at waist height. Work with plastic on the floor aroound you so that glass does not spread around your home. Use a separate sturdy bin for glass waste, and dispose of it separately.