The Function of Sound and Form
There's not much of a lecture this time; most of the information is in your reading assignment. But I do have a couple of additional hints.
Instead of looking at rhyme and meter as a separate issue, look at it as part of the theme. In other words, how does the rhyme (or lack of it) and meter (or lack of it) complement the subject matter or the theme of the poem?
In "My Papa's Waltz," for example, there is a definite meter, but it's broken on many lines--i.e., it has an extra syllable or maybe not enough syllables. The regularity is broken, just as the boy's waltz with his father is broken by the father's drunken missteps, and just (perhaps) as the boy's relationship with his father is "broken."
In poems where there is no regular rhyme or meter, look at the way the author has chosen to group the lines, where the lines end, how words are (or aren't) capitalized, etc. Even in open form poems, the poet is using the form of the poem to help complement the theme or subject matter. In "Hope," for example, the author has chosen to place the word "missing" all alone on its line, perhaps because it is the all-consuming fact of the parents' lives right now.
Other than that, the information is in the chapters on "Sound" and "Form" in your reading assignment. But feel free to ask if you have any questions about it.