A motif is a recurring subject, idea, or theme. Sonnet 130, which is devoted to the dark lady, emphasizes her coloring, so colors would be a motif in the poem. As a matter of fact, the first 5 lines of this 14 line sonnet are all about colors, red, black, white, dun. The speaker notes her "black eyes and hair," and describes her shortcomings by noting all the colors she does not possess.
Another motif found in Sonnet 130 is the five senses. The speaker compares his mistress to perfume (smell), roses (sight), music (sound), wires (touch), and the only sense he does not use is taste. Again, the poem negatively emphases his mistress' deficiencies, stating that all of the beautiful items mentioned are far better than she.