IRAC is a legal writing style used by some students on exams.  The acronym stands for Issue, Rule, Analysis, Conclusion.  You absolutely should write in IRAC or some other very organized manner.  This point cannot be overemphasized!  If you stubbornly refuse to write in IRAC, at least come up with some formatted writing style.
    IRAC makes your paper organized and easy to read.  Law students are capable and competent.  Going into the exam, you can bet that your classmates know the law.  The little things will make the big differences come grading time.  When prof's are looking at hundreds of exams for grading, they naturally are made happy by those exams that have been well formatted and are easy to read.
    Let's quickly go over a short tort's fact pattern to illustrate IRAC.  Read the sample fact pattern below:
    X, Y, and Z decide to rob a bank, they draw up a contract stating so, and all 3 sign.  X is to drive the getaway car, while Y and Z rob the bank.  On the day of the robbery the three men approach a farmhouse to steal the car they will use in the robbery.  They hot wire the car and drive away.  While driving away in the car, the farmer sees the robbery taking place and shoots at the men.  One of the shots strikes X in the back.  X's injuries are such that he will be of no use driving the get away car, so Y and Z decide to let X out of the car now, so X won't bungle the robbery.  X is let out and Y and Z continue down the country road 20 miles to the nearest town where the bank they plan to rob is located.  Carrying two loaded rifles and two bags, Y and Z enter the bank simultaneously.  Y yells "freeze, this is a hold up".  To show they mean business, Y cold cocks Mr. Bank Patron with the butt of his gun, knocking Patron to the ground and bloodying Patrons nose.  Y then yells for everyone to "get down on the floor and don't move.  If you move, you're dead".  The tellers are ordered to fill the bags with money, which they immediately do.  Y and Z take the bags, tell everyone to remain on the floor, and run out the door.  Police are waiting outside, a shoot-out ensues, and Y and Z are both killed.  X also dies of his injuries. 

    Discuss the issues.