And the startled little waves that leap In fiery ringlets from their sleep (3-4)
The image of the waves leaping in "fiery ringlets from their sleep" anticipates the meeting at the end of the poem where, presumably, the woman awakes from her sleep and participates in a moment of passion with the speaker. The speaker interprets the waves as an anticipation or foreshadowing of a moment later in the poem when love will be an important emotion.
Then a mile of warm sea-scented beach; Three fields to cross till a farm appears (7-8).
We associate farms with productivity, with the growing and harvesting of food. In a sense, the farm is sort of a symbol for the consummation of a relationship, for the procreative aspect of a sexual relationship that seems to be hinted at in the meeting at the end of the poem.
A tap at the pane, the quick sharp scratchAnd blue spurt of a lighted match (9-10)
The striking of the match suggests, to some degree, the emergence of a dormant passion, a kind of awakening, anticipated earlier with the leaping waves and given its final form in the "voice less loud" that responds to the speaker's tap at the window. Furthermore, the association between love, passion, and flames seems to be at work here.