Example conclusion:
"The end of "The Great Gatsby" is extremely effective. It is deeply moving and skillfully concludes many of the novel's major themes. It is largely responsible for my enjoyment of the novel because, despite its cynicism, it is both suitable and poignant. Without it, much of the novel's deeper meaning would be lost."
Not exactly ground-breaking, I know, but given the constraints of time, not too bad.
By the way, if anyone ever is given an example essay on Carol Duffy's poem "Shooting Stars" issued by the SQA, be sure to burn it because it is awful (the answer, not the poem).