Here's some follow up to the assignment from the first lesson.
The examples from Richard Peck, “Well, I’m an old sod-bustin’ son of the soil . . . I got more toes than teeth,” and “They’s green as gourds and never seen nothing,”
are great because they're memorable. The image of someone with "more toes than teeth" is an image that's going to stick in my mind in an amusing way. And what author doesn't want their characters to stick in the reader's mind? If these authors had not used alliteration in their descriptions, they wouldn't have been as memorable or funny.
Here's an example (okay, it's not as brilliant as the ones above) from my own book, The Beholder: "We’ll all end up sleeping in ditches and begging bread."
I originally wrote something like "begging door to door," but that didn't have the same flow as "begging bread." Here's another: "She sat listening, waiting, and finally heard horse hooves clatter on the hard-packed earth." This one has the word "clatter," which is an example of onomatopoeia, a word that sounds like its meaning. These "sound words" are great for adding a little oomph.
I will give a warning now: Be very careful about using too much of this type of rhetorical device. Alliteration, assonance, consonance, and onomatopoeia are best used in moderation. Don't force it or use it too much or your prose will come off sounding hokey, like you're trying too hard. However, if you write poetry, you can experiment with them forever. But for novels and short stories, too much is, well, too much.