Learning imposition can be used with evocation rituals to make the experience more vivid.

Imposition is the mental skill of giving yourself controlled hallucinations. People often begin learning this skill with simple exercises, like looking at two lines drawn on paper and visualizing a black line connecting them until one begins to appear as your eyes fatigue. Eventually, you make more complex shapes and do so faster.

Evocation is the act of summoning some type of entity or spirit. There is a great variation in technique, although people often start with something that puts them in touch with the feeling of what they want to contact (so they do something symbolic, like recite a poem or leave an offering of something associated with the entity,) while going through a ritual that is only used for summoning/evocation (only using the steps of one ritual for one purpose keeps the ritual associated only with that purpose in your mind, which makes the psychological state attained by magic practice much more distinctive, nuanced, and powerful.)

With imposition, it is possible to project your mental environment or external state into the real world around you, and if you are attempting to summon an idea or entity then this skill can be used to make the experience more complicated and clear for you.