Here are the criteria for evaluation:

Does the introduction orient the reader to the subject?  In particular, does it establish a context for argumentation and decision-making (that is, address why its worth arguing about this)?
Does the introduction contain a clear thesis that identifies the author’s central, overall argument claim?
Does the body of the paper contain a reasonable number of discrete main points?
Are the main points stated clearly as supporting arguments?
Are these supporting arguments arranged effectively?
Are these supporting arguments developed using good evidence and sound reasoning?  Do these supporting arguments contain counterarguments, when appropriate?
Do theses supporting arguments cover the full range of relevant issues needed to make a prima facie case?
Does the conclusion reinforce the author’s overall claim?
Does the conclusion emphasize a convincing vision of the case?  That is, does it make your case seem appealing, not merely justifiable?
Is the paper well-written?