What are the major neoclassicist themes in an Essay on Criticism by Alexander Pope?

An Essay on Criticism by Alexander Pope encapsulates the Neoclassical literary theories of eighteenth-century England, a period sometimes referred to as "Augustan" for the way writers self-consciously imitated the classical writers of Rome during the period of Augustus, especially Horace.

The first typically Neoclassical theme is the reverence for the great writers of the past. Rather than valorizing originality or eccentricity, Pope advocates synthesizing meticulous craftsmanship with universal and rationally discoverable intellectual and human truths....

An Essay on Criticism by Alexander Pope encapsulates the Neoclassical literary theories of eighteenth-century England, a period sometimes referred to as "Augustan" for the way writers self-consciously imitated the classical writers of Rome during the period of Augustus, especially Horace.

The first typically Neoclassical theme is the reverence for the great writers of the past. Rather than valorizing originality or eccentricity, Pope advocates synthesizing meticulous craftsmanship with universal and rationally discoverable intellectual and human truths. He sees human nature and the natural world as part of a vast, ordered cosmos with a divine creator and sees all great art as echoing that universal divine order. What makes the ancient poets great for Pope, and defines the impetus behind the Neoclassical emulation of them, is precisely their universality. Poet phrases this eloquently in the lines:

But when t’ examine ev’ry part he came,

Nature and Homer were, he found, the same. ...

Learn hence for ancient rules a just esteem;

To copy Nature is to copy them.

Next, Pope admires balance and symmetry in all aspects of poetry, with the poetic form suited to the subject matter and the language clear and natural, as opposed to technical and contorted, as he thought the case with the Metaphysical poets. 

Another major Neoclassical element in the poem is its satiric genre. Satire was the mode par excellence of Augustan poetry, using wit to deflate the pretensions of what the Augustans saw as radical innovations and grandiose posturing.