Ritual

Rituals are higly complicated spells. They are done when a wizard can't summon the required focus needed for a spell.

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 circle with chalk 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 conceps like the four elements or the mind body and spirit, any other magic tied to the wizard.

Materials
Crystal: represents earth

Pictures of loved ones: heart

Hair/blood/etc.: focuses spells on people eg tracking spell.

These are examples of some of the many materials that could be used in a a certain ritual.

Uses of a Ritual
Tracking spells

Summoning entities

Trapping entities