The hazy glow of a lantern caught the metallic edges of the paper, making them blaze a shimmery gold, the color of magic and wishes and promises of things to come.
-- Narrator (chapter 2)

Importance: This is the first look Tella has of the invitations to Caraval. The description of colors is an example of the fact that Scarlett sees colors in association with many things, including emotions. This statement can also be read as a foreshadowing of the game at Caraval, and the fact that Scarlett and Tella will be there.

So while we want you to get swept away, be careful of being swept too far away. Dreams that come true can be beautiful, but they can also turn into nightmares when people won't wake up.
-- The Girl on the Unicycle (chapter 8)

Importance: Scarlett is at the gate of Caraval, about to enter, when the girl warns her about being too caught up in the game. The warning hints...