"The Question for the performer in forming an effect should not be “what can I do?” or “How can I use this?” The ultimate question that will lead to truly magical effects must be spectator-centric.
“What would really freak out a spectator?” What would convince them that I possessed this power?” “What would move them in a particular way?” And "What would they want to see?” Only after answering this, I think, one should ask – “And what then can I provide to take it a step further?”
Derren Brown - (Pure Effect.)