"Barter" is made up of two major ingredients: ideas and imagery. These ingredients are no good if you're making cookies, but they work great for making poems. The ideas come in the form of intangible things (things you can't touch or see) like "loveliness," "wonder," "peace," and "ecstasy." When Teasdale gives us imagery, it's almost always nature imagery. No cars or boats or buildings in this one.
Line 3: Nature pops up first in the form of waves crashing on cliffs. It's a nice image, and Teasdale knows how to get the most out of it.
First, she uses color. The "blue" waves are "whitened" against the cliff. This sets up a strong contrast between the colors blue and white. We even get a sense of the color black, from the cliffs, even though it isn't mentioned specifically. Most of us are going to picture the ocean cliffs as dark or black.
Contrast can intensify our response to a poetic image just as it can in a photograph. When a photo has sharp contrast between colors, or even in the grayscale of a black and white photo, the image is more interesting visually and draws us in.
Teasdale also gets a lot of bang for her imagery buck with sound. Here again, she doesn't mention sound specifically, but we bet you could hear those waves crashing against the cliff just by her describing the visual elements of the scene.
Line 9: This time, Teasdale gives us some nature smells—don't worry, just the good kind.
The "scent of pine trees" is something most of us can recall pretty easily. Just think back to that great Christmas tree smell that told you presents were on the way.
Teasdale ups the sensory level a bit by including "in the rain." Now we have that rainy-day-in-the-country smell too, the wet soil and foliage.
Teasdale also gets some auditory action going here. We can practically hear the rain falling through those trees. Here once again, she doesn't mention the sound explicitly but it's there. We add it ourselves based on the other sensory details in the image.