1. Compare item to list[middle]. If item = list[middle], then we have found it. If item < list[middle], then look in the first half of the list. If item > list[middle], then look in the second half of the list.
2. Redefine list to be the half of the list where we continue our search and repeat the first step.
3. Stop when we have found the item or know it is missing. We know it is missing when there is nowhere else to look and we still haven't found it.

   Length of List     Sequential Search     Binary Search
          10                   5.5                 2.9
         100                  50.5                 5.8
       1,000                 500.5                 9.0
      10,000                5000.5                12.4

1. The length of the list to be searched
2. Whether or not the list is already sorted
3. The number of times the list is to be searched

A graphical view of this binary search method is here.