Rituals

Rituals are highly complicated spells

Basics
Wizards use rituals because they are unable to focus on all the parts of a needed spell. It makes the spell easier to do. Rituals can be as basic as making a magic circle to a Sanctum Invocation. High level rituals are extremely complicated and difficult to get right. The variables in a ritual could include the direction a certain candle is pointing, materials that have certain meaning to the wizard, ties to certain spiritual concepts like the four elements or the mind body and spirit, any other magic tied to the wizard.

Materials
Some examples of materials that could be used include: a crystal (representing earth), pictures of loved ones (representing heart), hair/blood/etc... (for when directing a spell towards a specific person or group of people), etc...

Uses of a Ritual
Rituals have a variety of purposes, the most common being tracking people down, summoning, and trapping individuals.