When people start off with magick they usually begin with general externals and specific internals.
By this I mean they begin with the externals of the ritual being rather generalized—everything colored red for added energy, for example—along with a specific intention such as bringing yourself more energy to "pull an all-nighter" studying for a test. For some people general externals and specific internals are effective enough and are all they will ever need or use.
However some people, including myself, want to use externals that are more specific. The idea behind this is that the more specific everything is, the more the magick is focused and directed toward your goal.
To this