Question

How is a poem created in a poet's mind?

Answer 1

a poet can see both moving objects and those that are stationary or even immovable you may take that as either a poetic metaphor or as psychological metaphor it works both ways

Answer 2

Poem is the best method by which one can express his sadness, loneliness, happiness and all kinds of feelings.

Well, I have written few poems so maybe I can help you :)

For different poets, the source of the poem is different. The poem can be created from anything, including non-living things and things which we cannot even see. For me, most times the source of imagination is my books. I was inspired from several stories. For William Wordsworth, a famous nature poet, the source of his poem " Daffodils " were the beautiful flowers.