"Do Not Go Gentle into That Good Night" is a villanelle, a verse form consisting of five three-line stanzas followed by a four-line stanza. The main feature of a villanelle is repetition according to a set scheme: The first line of the first stanza is repeated as the last line of the second and fourth stanzas. The last line of the first stanza is then repeated as the last line of the third and fifth stanzas. This creates a pleasing sense of rhythm and makes it easy to remember the two most important lines of the poem, which are repeated together in the final two lines.
Within this form, Thomas also uses apostrophe. In apostrophe, the poem's speaker directly addresses an absent person or object. In this case, the speaker is talking directly to his father. This adds to the emotional force of the words. Thomas uses personification, which is when objects, concepts, or animals are given human characteristics, when he refers to "frail deeds" dancing as if they are human. Thomas employs alliteration in phrases such as "blind eyes could blaze" and "deeds might have danced," and he employs assonance in such lines as "words had forked."
Thomas also uses imagery throughout the poem in words such as "lightning," "light," "sun," "blaze," and "meteor" to paint a visual picture of the way old men should fight back against death. He employs a simile when he compares old men's blind eyes to "meteors."