You can analyze descriptions in a number of ways. One way is to decide if the author means the description "literally" or "figuratively."
Literal means that the author means exactly what he or she writes. For example, "A few cold drops of rain fell on the children's noses and their cheeks and their mouths. The sun faded behind a stir of mist. A wind blew cold around them. They turned and started to walk back toward the house, their hands at their sides, their smiles vanishing away." This is a great, precise description of the start of a rain storm. The author means exactly what he says.
Figurative means that words are used in a way that is different from the usual meaning. Figurative language creates a picture in your mind. For example, "The children pressed to each other like so many roses, so many weeds, intermixed, peering out for a look at the hidden sun." The author does not mean that the children are actually roses or weeds. This description makes you think of roses and weeds crowded together, then relate that to a crowd of children trying to see the sun.