For most things, I'm assuming like you would at a fair. At least for the booths and panels, I think you get in line to attend, depending on the staging area for the panel (several of them might be in the conference rooms instead of the main hall).
And many people in cosplay are willing to stop for photos, especially with other cosplayers, at least based on the experience of others at other cons. There will be the standard cosplay masquerade, I'm sure, and you can generally see who people cosplayed as at that, generally the best ones enter the competition.