I'd add that a great way to maintain cognitive load is to keep specifically pointing out features of the thing being sold in a way that makes the mark feel a need to judge each one (most effective if it's a physical thing).

This happened to me when I was buying a bag two days ago! I did find myself wondering, after the fact, why the employee was pointing out vaguely positive but basically inconsequential facts about it. This model makes sense to me, though I doubt the guy was explicitly deploying the strategy rather than just running a pattern that he'd learned was successful. (I believe this because my prior is that people aren't often explicitly strategic).

I did buy the bag, in the end.