The most obvious device used by Burns in this poem is personification: the entire poem is an address—or apostrophe—to a mouse, making the assumption that the mouse has human attributes, motivations, and understanding. Indeed, the most famous lines from the poem group the mouse together with humans as capable of "scheming": "the best-laid plans o' Mice an' Men / Gan aft agley."
The poem's structure utilizes a steady repeating rhyme scheme of AAABAB, which helps sustain its rhythm and internal cohesion. Burns also uses alliteration repeatedly: examples include "thou art no thy lane," "weary Winter," "cruel coulter." You will be able to spot other instances of this yourself.
We can also, arguably, spot a continuing metaphor in the description of the mouse's hole as "housie" and "cell." This continues the theme of personification, by which the mouse is addressed as if it is human and has equal regard for its home as people do. Burns suggests that we should have more consideration for our fellow mortal creatures, rather than assuming they are merely simple animals.