In both soliloquies, Juliet is waiting, and her wait is related to feeling of love. In Act 2, Scene 5, she is waiting for Nurse to bring news from Romeo about wedding plans, while in Act 3, Scene 2, she is waiting for Romeo to come to her room for their wedding night. Since both soliloquies have to do with waiting and love, both are filled with images related to waiting, speed, and love.
In Act 2, Scene 5, she is feeling particularly annoyed because Nurse has not yet returned, and it is already high noon when Juliet sent Nurse to meet Romeo and nine in the morning. But more importantly, Juliet is very eager to learn if Romeo really does intend to marry her. Hence, Juliet complains about Nurse's infirmity, possibly obesity, and wishes that she could know Romeo's mind just by hearing his thoughts, as we see in her lines:
O, she is lame! Love's heralds should be thoughts,
Which ten times faster glide than the sun's beams
Driving back shadows over low'ring hills. (II.v.4-6)
In these lines, she uses a metaphor to describe the speediness of love's thoughts, saying that the thoughts of love move "ten times faster that the sun's beams." She continues her analogy to describe the sun's beams chasing shadows away from the hills. Comparing love's thoughts to the image of sun beams helps paint the picture of warmth and happiness for the reader. Even though Juliet is eagerly waiting, her general attitude is happy because she is in love. In addition, sun beams move fairly slowly, so the image of moving sun beams helps characterize for the reader her feeling of impatience.
In Act 3, Scene 2, Juliet again uses sun imagery and figurative language. But this time, she uses them to describe the haste she is longing for. We see her using a sun image figuratively in her very first few lines:
Gallop apace, you fiery-footed steeds,
Towards Phoebus' lodging! Such a wagoner
As Phaeton would whip you to the west
And bring in cloudy night immediately. (III.ii.1-4)
These lines are referring to the Greek sun god, Phoebus Apollo, who was believed to ride his chariot across the sky to direct the sun into both sun rise and sun set. Hence, when she refers to the "fiery-footed steeds," she is referring to both the sun and Apollo's chariot because the chariot represents the sun. She is using the analogy of likening the sun to Apollo's chariot in order to conjure up the image of speed. Not only is she metaphorically referring to the sun as Apollo's chariot, she is also personifying the sun as his chariot horses, which are both forms of figurative language. Since she is using the figurative language to express her desires that the sun would set faster, she is, again, using the image of the sun and its slowness to characterize her feeling of longing and waiting.
Both scenes begin with an anxious soliloquy from Juliet. She is eager to hear news of her lover Romeo from the Nurse and laments not being able to see him. In Act 2 Scene 5 Juliet is waiting from the Nurse to see if she can marry Romeo, and in Act 3 Scene 2 she waits to meet Romeo in her bedroom the night following their marriage.
The structure of the two soliloquies are very similar. Both are spoken by Juliet, both take place at the beginning of their scene, and both have Juliet waiting for news of Romeo to arrive through the Nurse. In 2.5, Juliet wishes her middle-aged Nurse to carry the message back to her with more speed, like "windswift cupid wings." In 3.2 Juliet is also impatient for the Nurse to arrive and tell her if Romeo will be able to meet her. When she spies the nurse, Juliet impatiently cries out, "Nurse, what news?" in both scenes.
There are some important differences, though, in the soliloquies. In 2.5, the setting is high noon, and Juliet has been waiting three hours for the Nurse. The imagery is of a bright warm day, "the sun upon the high most hill" and Juliet wishes her messenger the Nurse to glide as fast as the "sun's beams." She worries that the day is slipping away too fast without any updates on her lover.
3.2, however, takes place as the sun is setting, and the "wings of night" bring in darkness. Juliet is eager for the day to end in this scene because it will mean alone time with Romeo. 3.2 foreshadows the upcoming fulfillment or consummation of Romeo and Juliet's marriage. The second soliloquy is filled with sexual undertones. Juliet wants it to be night already ("spread thy close curtain, love-performing night") so Romeo can come and consummate their marriage. Juliet says, "I have bought the mansion of a love and yet not enjoyed it," meaning she has married Romeo but not yet slept with him and fulfilled the proper roles as wife and husband.
Juliet repeats the word "black" several times in 3.2, which makes sense because she is speaking about the night, but it might also foreshadow the coming darkness and death of the play. 3.2 is definitely a darker, sadder scene that 2.5, and Shakespeare could be showing this through the darker imagery. 2.5 ends with the Nurse giving Juliet happy news: that she will in fact be able to marry Romeo. 3.2, however, has the Nurse bringing in tragic news: Tybalt (Juliet's kin) has died and Romeo has been banished as a result. The shift from good to bad in the two scenes foreshadows the even greater tragedy waiting to hit Romeo and Juliet later in the play.