Like many of his poems, "The Road Not Taken" shows Frost's strong connection with nature and natural beauty. He takes time to explain that the forest is "yellow," meaning that it is Fall, and that the path "bends in the undergrowth," showing how the forest (life) hides the future.
The narrator also mentions that his chosen path is "grassy and want[s] wear," meaning that the paths are not paved roads but dirt, meant for foot travel. Both paths are covered in leaves, reinforcing the Fall theme from before and the lack of travelers. Most of the imagery in the poem is visual in nature; the narrator doesn't mention bird, insect, or wildlife sounds, but the reader can imagine that the path crunches underfoot, seeing as how it is covered in leaves. Other sounds can be assumed from the fall setting, but none are actually mentioned. Similarly, there are no smells, tastes, or touch sensations mentioned; the poem is more about trying to decide the future based on what is known at the moment.
The last important visual image mentioned is "the morning," meaning that the narrator is just starting out on his journey. This symbolizes a still-young person, with many choices ahead, making one of his first major decisions in life. As the day (life) continues, he will look back on the "morning" and think about his decision, wondering if it was the correct one.