When Carrie and Patrick are talking on Perry street and he's explaining about him being an alcoholic, two women in the background pass them twice.
In the tantric sex class scene, Charlotte's hand holding the notebook switches position.
Throughout the series, we hear Carrie refer to her apartment on East 72nd and 3rd Streets - towards the end of this episode, her date walks her to her building as we can see a distinct "W 4" (West 4th) sign behind them.