You need to think of significance of factors here. I would say they are the following in this order: General Intelligence, Stress Level, Familiarity with the t

You need to think of significance of factors here. I would say they are the following in this order: General Intelligence, Stress Level, Familiarity with the task at hand, Good night's sleep, Coffee/tea/other stimulants, Nutrition, Exercise I think the single most important in this list is stress levels which can really lower your iq by dozens of points at a particular moment. Everything except the first is modifiable.