Step 1: Narrow down your list of potential candidates based upon their skills, education, and experience. Some might divide their piles into leading candidates, secondary potentials, and discards.
Step 2: Review your interview notes and determine which candidates gave the best answers and seem to have the most relevant knowledge for the position. Look for critical and "out of the box" thinking.
Step 3: Review the resume for complementary employment experience that may make one candidate more valuable than another. Sometimes it is better go broad than specific.
Step 4: Think about the type of personality you must work with and whether or not you want someone who is open minded and willing to learn or you want someone who is more forceful and direct.
Step 5: Go with your gut feeling. Sometimes you might pick up on cues that tip you off to the potential nature and goals of the person.