Romanticism was a shift from a Neo-Classical period marked by eloquence of form and tradition to a movement more centered on individual experience, the imagination, and emotion. This movement shifted away from tradition. Romantic poets wrote with less rigid structures and forms. Poetry took center stage during the Romantic period because many Romantic writers believed poetry was the more creative and profound genre. Some scholars also claim that the rise of female novelists caused some of these Romantic poets to scorn novels and praise poetry.
To put it in a clear-cut way, Romanticism is noted for a more free style and themes of imagination, individual experience, inner visions and dreams, connection to nature, and the importance of emotion in the creation and experience of art.
These themes show a more subjective approach to art. Emphasizing the imagination, Romanticists sought to be more expressive in terms of emotion and creativity. And this emotion and creativity resulted in personal works such as Wordsworth's "Lines Composed a Few Miles Above Tintern Abbey" and imaginative works such as Mary Shelley's Frankenstein. Note the Romantic's emphasis of individual experience as illustrated when the creature becomes the narrator.
Because Romanticism was a celebration of the individual, there were many works (notably those of the Romantic poets such as Wordsworth and Keats) who looked to nature for inspiration (rather than civilization which was entrenched with organization, rigidity, and conformity to tradition and progress). Romanticism was not necessarily a rebellion against society. It was a movement that emphasized emotion, the imagination, the inner self, and subjective experience. For the Romantic poets, it just seemed more "natural" to find inspiration alone in nature, rather than to find it in society, the place where traditions and social organization take precedence over individuality.
In "Ode to the West Wind," Percy Bysshe Shelley writes of his desire to find poetic inspiration in nature. In this individual experience, he longs to feel connected to nature as if the wind itself, as it moves the air, could emotionally and creatively move him as a poet:
Make me thy lyre, even as the forest is:
What if my leaves are falling like its own!
The tumult of thy mighty harmonies
Will take from both a deep, autumnal tone,
Sweet though in sadness. Be thou, Spirit fierce,
My spirit! Be thou me, impetuous one!