The poem seems to begin with the speaker talking to a shoe, and telling it that it doesn't "do," or work for her, anymore (the repetition of "do" here is technically an example of a poetic device called antanaclasis). The speaker then declares that she has been stuck inside said shoe for her entire life, without fortune or access to the colorful outside world, scared of making the slightest sound.
Of course, the speaker isn't actually talking about a shoe. The poem's title is "Daddy," and the "You" the speaker addresses in the first line—via apostrophe—is really her father. The "black shoe" is likely a metaphor for her father's memory, which has a terrible hold on the speaker. The oppression the speaker feels—her poverty, her fear, her inability to breathe—are directly attributed to her father. The speaker is aware of this, and the poem begins with her renouncing her father's memory: "You do not do, you do not do / Any more, black shoe."
The first stanza of "Daddy" has a sing-song rhythm created by the repetition (more specifically, the epizeuxis) of "You do not do" in the first line and the strong assonance of /oo/ sounds, particularly at the ends of lines. In fact, it is not only reminiscent of a child's nursery rhyme; the image of the speaker living like a foot in a shoe is a reference (a.k.a. an allusion) to the famous nursery rhyme that begins: "There was an old woman who lived in a shoe." Together with the title, the fact that the first stanza evokes a nursery rhyme immediately infantilizes the speaker. Despite being thirty years old, she refers to her father as "Daddy" and to a sneeze as an "Achoo."
Moreover, it's clear from her description of the "black shoe" in which she is trapped like a foot—"Barely able to breathe—that her situation in life is oppressive. The image of the foot is telling. If the body is a hierarchy, then the head is in control: it exists at the top, and makes decisions for the entire body. It follows that the foot is at the bottom, bearing the weight of the entire body.
The shoe itself is also an oppressive image. Inside the shoe it is dark and there is no air. It's not hard to understand why the speaker would want to free herself from such an existence.