Meditation in my opinion is the biggest basic practice of a magical caster. After that the basics include chakras, tools, color correspondences, moon phases, elements, and the wheel of the year. A basic understanding of gods is also good to have.
Your meditation should allow you to gather, manipulate, and redirect the energy inside of you in order to cast spells or other magical workings. Make sure you are plugged into the universal power supply first before thinking you can watch and infulence the tv of life.