The concerns on the part of CBP when someone is seeking admission as a B-1 business visitor are the appropriateness of the applicant's proposed activities and the applicant's ties to home/intent to return home (Canada). So you want to keep in your back pocket documents that address these concerns, such as a foreign lease agreement, foreign pay statement, and evidence of the purpose, such as a printout of the conference being attended or a letter of invitation. It's also really important to be prepared to provide specifics about your purpose, who, what, when, and where.