Maybe it's an awareness, a product of reading both classic literature and poetry; maybe it's a natural skill born of an ear for sounds; maybe it's just overwriting and hokey, but I seem to use a lot of alliteration in my writing.
There is a softness to alliteration, even with hard sounds such as "the great green grass." I personally like this effect because it emphasizes while tying together a thought into a package. Words become a palpable image that remains in the mind–much in the manner (whoa–didn't plan that one!) of nursery rhymes.
It can get overdone though and I'm trying to make myself more aware of them so that they do not take away from story but rather enhance a natural rhythm that carries a reader along.