The main attributes Pope satirizes in The Rape of the Lock are those of people overly concerned with appearances and with trivial social manners and customs. He employs mock-heroic language, a kind of parody of the epic poets of antiquity, Homer and Virgil, to emphasize ironically the unimportant obsessions of people in British upper-class society.
Much of the poem is devoted to describing the glittering appearance of the wealthy young people of the time. The focal point is the heroine (or we should say, mock heroine) Belinda, a beautiful young girl who comes across as shallow and vain in the extreme. Yet the miracle of Pope's verse is that this type of critical portrayal is done so playfully that it's not offensive. Belinda is the center of attention at a party but chiefly because of her looks rather than any deeper qualities she might (and perhaps does) possess:
Fair Nymphs, and well-drest Youths around her shone.
But ev'ry eye was fix'd on her alone.
On her white breast a sparkling Cross she wore,
Which Jews might kiss, and Infidels adore.
It has rarely been noted, but the second couplet is actually a veiled commentary on religious hypocrisy. Much of The Rape of the Lock and its criticism of society can be understood in the context of Pope's own biography. Pope was an outsider in Britain because he was a Roman Catholic, but also because of his physical appearance as a little person. The poem fixates ironically on the glamour of the people and their society to which Pope had an entry only through his intellect—his precocious and astonishing ability as a poet. His message is that the world as a whole overrates not only physical beauty and outward appearance but trivialities in general.
There is also a proto-feminist moral in the poem, though it's a slightly compromised one. The keynote speech, if we will, of the work is given by Clarissa after the "damage" of the severed lock of hair has been done:
Say why are Beauties prais'd and honour'd most,
The wise man's passion, and the vain man's toast?
Why deck'd with all that land and sea afford,
Why Angels call'd, and Angel-like ador'd?
Why round our coaches crowd the white-glov'd Beaux,
Why bows the side-box from its inmost rows;
How vain are all these glories, all our pains,
Unless good sense preserve what beauty gains.
It is a message relevant not only to women's issues but to any situation in which the deeper and more significant qualities of people are ignored in favor of superficial ones. Yet Clarissa herself hasn't been shown as a totally neutral party, given that she has passed the pair of scissors to the Baron so he can snip Belinda's lock. There would appear to be an element of envy in Clarissa, perhaps realistically conveyed by Pope, but it does not invalidate the powerful theme of the work, stated in the opening couplet, especially the second line:
What dire offense from amorous causes springs,
What mighty contests rise from trivial things.