Five predominant elements of Transcendentalism are nonconformity, self-reliance, free thought, confidence, and the importance of nature. These concepts are liberally sprinkled throughout Emerson's essay "Nature."
When Emerson says that we should "demand our own works and laws and worship," he espouses nonconformity.
Free thought is similar to nonconformity. Emerson encourages readers to avoid doing what their peers or predecessors do; rather, they should think for themselves. In the introduction, he bemoans the fact that "speculative men are esteemed unsound and frivolous." This suggests he values speculation, or free thought.
In Chapter 1, Emerson asserts that, as long as he has nature, he can be complete. His belief that "in the woods ... nothing can befall me in life" shows self-reliance and confidence.
The key tenet of Transcendentalism displayed in "Nature" is the importance of nature. That is what Emerson is writing about, after all. He begins by stating in the introduction that "all science has one aim, namely, to find a theory of nature." In Chapter 1, he discusses the stars and how we take them for granted, but that they nevertheless "awaken a certain reverence." He suggests that, although no one "owns the landscape," the poet who appreciates it possesses it in a sense. He says that nature can produce "a wild delight" in a man even amid sorrows. He becomes eloquent when describing the effect of the woods on him. It makes one feel perpetually young, and "all mean egotism vanishes." He feels as if he is "part or particle of God" when he is out in nature.
To identify elements of Transcendentalism in "Nature," keep looking for expressions of nonconformity, free thought, self-reliance, confidence, and the supremacy of nature.