They wanted to use plain language, or, as Wordsworth put it, "language really used by men."
They wanted to focus on simple people and rural situations. Their goal was to talk about the common man.
Poetry, he said, is "the spontaneous overflow of powerful feelings." Wordsworth described a powerful feeling that overcame people when they were in the presence of the raw beauty of nature. This is called an apotheosis. This powerful feeling was the inspiration for poetry.
The poet was also a deep thinker, and thoughtful recollections of powerful feelings were the source of poetry.
They wanted the focus in their writing to be on the power of nature around them.