When Card sorting I like to create some cards that already have a contextual bearing towards a users mental framework and taxonomy. This can be extremely helpful in terms of prototyping a user flow and building a sitemap in real time with a group of people. I create cards for both the main content sections and sub stories.

Always bring blank cards to ref on and drop in new directions and insights along the ideation exercise. Its a great design thinking exercise that always leads to a greater position of understanding post meeting.