There are various drywall cutting tools and depending on the job you are doing, using the wrong tool could make the task much more difficult.
The Right Tools
You can get a complete set of tools that are used for cutting drywall for about $40 at any local home improvement or hardware store.
The tools that you will need are:
Most cuts made on a drywall hanging job have only three steps – scoring the front paper, snapping and folding the sheet open, and cutting through the paper on the back. These cuts will be done using the rip saw.
The keyhole saw will be used for smaller cuts (for instance electrical box openings) and a coarse-tooth saw will be used for larger cuts – doors or windows.
Use the 4 foot square to ensure that all cuts are made straight, as the rule with any sort of cutting, measure twice and cut once to prevent wrong measurements.