experience in the world and his or her interpretation of that experience...

Questions were appearing with regard to the doctrines of the church and traditional interpretations of man's place in the world. 

Writing itself changed dramatically, though only for a short period of time: the Romantic movement would only last about forty years, but its influences would be much more far-reaching:

For the romantics, poetry was believed to be the highest form of literature, and novels were regarded as a lower form of writing...

Many things influenced these men, considered first-generation Romantic poets. One was revolution, as seen in America and France. These poets (and others) "wrote glowingly" of the revolution. Another major concern was Industrialization, which dramatically changed the face of the world—machines were now used to manufacture in quantity. With the population growth, there were more people to work in the factories, however, this included women and children. The working conditions were extremely harsh. Children were also used in mining; it was not unusual for these youngsters to lose a hand or foot, or be killed. There were no rules to protect these workers. Housing was erected, but these people lived in squalor. 

Factories of this time caused massive pollution, destroying the natural beauty of the world.

The industrial changes convinced many romantics the natural world was purer than the industrial one, and that nature was a place of spiritual truth, release, and renewal.

The Romantic writers were concerned with social issues of the day. Lyrical Ballads was a collaborative effort between Coleridge and Wordsworth. As champions of nature and those abused by society, they wrote about man and nature; love; the supernatural; and, the downtrodden and abused, including:

...the plight of old hunters, insane mothers, and the victims of England’s various wars abroad.

Wordsworth and Coleridge both wrote poems about the individual that...

...explore one man’s difficult attempts to understand who he is in relation to the natural world.

William Blake was a Romantic writer as well, but his work found a slightly different focus. Blake was a mystic:

Blake claimed to have received angelic visitations and other visionary experience even as a child.

His writing was greatly influenced by the Elizabethans, not embracing the lyrical style of Romanticism as greatly. Blake was more influenced by radicalism, associating with people such as Thomas Paine, Mary Wollstonecraft, etc.

These radical views extended most especially to Christianity—he wrote parodies and satires about religion, specifically Swedenborgianism (as seen in The Marriage of Heaven and Hell. While his religious views would shift in his life...

...he maintained his attack against conventional theology and moral codes...

Overall, whereas Coleridge and Wordsworth wrote of nature, an idealization of women and children, the supernatural and concerns over industrialization, etc., Blake was more focused on religion.

Additional Source:

http://www.enotes.com/romanticism

http://www.enotes.com/poetry-blake-salem/poetry-blake