Some parts already exist in the system, while others can be added to create the right feel.
Different traditions will of course emphasise different laws, which adds to the feeling. Magick conforming to the laws will be easier to work and more powerful, since it follows the way humans think more closely. The descriptions of the laws below is taken from an old posting by Michael Barlow in an Australian newsgroup, which have since then spread across the net. The most basic of laws. Understanding brings control.