Sensory details refer to the five senses (sight, sound, touch, smell, and taste) that writers use to call readers attention.
Three sensory details from Chapter 3 that show how extravagant Gatsby parties are can be, for example, the following excerpt:
[...] At least once a fortnight a corps of caterers came down with several hundred feet of canvas and enough colored lights to make a Christmas tree of Gatsby’s enormous garden. (Sight sensory)
[...] On buffet tables, garnished with glistening hors-d’oeuvre, spiced baked hams crowded against salads of harlequin designs and pastry pigs and turkeys bewitched to a dark gold. (Sight sensory)
[...] and now the orchestra is playing yellow cocktail music, and the opera of voices pitches a key higher. (Sound sensory)