Cleomelia's beauty
Cleomelia's beauty is a key motif in the text and is referred to often. This is what attracts many suitors to Cleomelia, and she uses her beauty to manipulate them.
Cleomelia allegory
Overall, we might see the text as an allegory. Arguably, Eliza Haywood was commenting on the fickleness of wealthy men, and how they were deceived and distracted by beautiful women, to the detriment of their own interests.
Letters
The vast number of letters sent between the main characters represents the complicated nature of Cleomelia's love life. Ultimately, this is something that she desires as she hopes to manipulate the men.
Idealism
It is implied that the men don't love Cleomelia truly, but instead project fantasies and ideals onto her. Ultimately, this symbolizes the tendency of people to idealize their love interests.
Wealth and class
Wealth and class are key motifs in the text, and characters are often distinguished by their "social rank." Cleomelia is attracted to her suitors due to their wealth and little else, revealing her motivations.