Interpret "A Ball is for Throwing" by Adrienne Rich. Specifically, how does alliteration, consonance, and assonance lend to the feeling of the poem?

Rich's "A Ball is for Throwing" argues that objects gain life and value only when they are used. She contrasts the ball sitting in a shop window, useless there, with the child's desire to put the ball into motion.
The tone or feeling of the poem is childlike, employing the simple words a child might use and a child's simple sentence constructions. It conveys the wonder of actually using a ball and contrasts this to Queen Victoria's unused doll house.
Alliteration occurs when words beginning with the same consonant are placed in close proximity. Consonance is similar, but the consonant sounds that repeat can be anywhere in the words in question. In assonance, vowels at the beginning of words in close proximity repeat.
Rich primarily uses alliteration to capture and emphasize the wonder of playing with a ball, such as in "rounding leap" and "longing rush" with their repetition of "r" and "l" sounds and in "flash of flight" with its repeating "fl" sound. We also feel the child's longing expressed through such alliteration as "beautiful ball," because the repeated "b"sounds bringing a sense of emphasis to those two words.
Consonance occurs in such lines as "See it . . . poised in the toyshop window." The repetition of "s" sounds in "see," "poised," and "toyshop" creates a sense of rhythm. So does the repeated "p" in poised and toyshop.
Assonance is less prevalent in this poem, but it can still be found in the repeated short "i" and "a" sounds at the beginning of words in the first stanza: "is it . . . is it . . . is it . . . it is" and "it does not exist at all." In these lines, the assonance is created by the simple, childlike sentence structure which shows how, in the child's mind, the ball is an object of desire because of its use value.
As you go through the poem, you should be able to find more examples of these three literary devices.