Wordsworth practiced what he preached in his Preface to Lyrical Ballads: his poems model the new kind of poetry he describes in this preface. The Ruined Cottage is a textbook case of a poem that illustrates many of the principles Wordsworth set forth, which changed the face of poetry. (Wordsworth's radicalism can be hard to understand, for his new kind of poetry has become what we view as ordinary poetry today: he had a huge impact.)

For example, Wordsworth argued for a language that was simple and easily understood by the common person, and we see this throughout the poem. One example is below:

nor could my weak arm disperse
The host of insects gathering round my face

Wordsworth also believed deeply in the power of nature to transport us to a higher emotional state—this is the lyricism he discusses in the Preface. In the quote below, he refers to the elms as a "brotherhood," personifying them, and his exclamation point emphasizes the emotional response he has to them:

a brotherhood of lofty elms,
Appeared a roofless Hut; four naked walls
That stared upon each other!

An extremely important tenet in Wordsworth's poetic vision was elevating the common man. This can seem ordinary to us, but it was a radical move in his time period, where most poems (excluding those of some predecessors such as Gray, Crabbe, and Cowper), treated the lower classes as "clowns," often the butt of ridicule. Wordsworth, however, aimed to show them as worthy of the highest respect, as in the following:

A virtuous household, though exceeding poor!
Pure livers were they all, austere and grave,
And fearing God

Wordsworth also emphasizes the importance of memory. The rustic man he meets had not only received a "precious" education through nature, he would, throughout his life, use nature as a touchstone for memory. For Wordsworth, remembering in tranquility the emotions raised by an encounter with nature was one of the key gifts the natural world offered:

He had received
A precious gift; for, as he grew in years,
With these impressions would he still compare
All his remembrances, thoughts, shapes, and forms

The poem emphasizes as well the Romantic concept, dear to Wordsworth: that nature is the best teacher, far better than any book. The rustic man might not have received a university education, but he received the best possible education:

the lesson deep of love which he,
Whom Nature, by whatever means, has taught
To feel intensely, cannot but receive....

That in our best experience he was rich,
And in the wisdom of our daily life.

Also like a good Romantic (and following his theory of elevating the common person), Wordsworth criticizes the wealthy and powerful in this poem:

Among the unthinking masters of the earth
As makes the nations groan.

The poem extolls the beauties and spiritual gifts of nature and memory while elevating and honoring the common person: this is Wordsworth and his Preface all over.