pros and cons of legalizing

Clearly and effectively advocate a position within the controversy. (you are for legalizing marijuana as long as the person legitimately needs it)

Establish your credibility as a believable witness and researcher

Draw upon at least four expert, published sources that argue a variety of

DIFFERENT perspectives:  you should include a fair summaries of all variety of different experiences: at least two arguments that most closely opposed your own perspective and at least two perspectives that support what you have come to believe

Incorporate effective rhetorical strategies, i.e., appeals to emotion (pathos), development of credibility (ethos), and evidence (logos), as well as thoughtful organization, strategic use of words, anticipation of opposition, etc