Even though "The Flowers" is not a long story, it is filled with amazing descriptions and details, and contains a profound message of lost innocence at the end. One way that Alice Walker emphasizes that messages is through contrast. Myop and her happy jaunt through the forest is described using very long sentences filled with flowery details of the beautiful day and Myop's happy mood. For example, take this sentence:
"She found, in addition to various common but pretty ferns and leaves, an armful of strange blue flowers with velvety ridges and a sweet suds bush full of the brown, fragrant buds."
Here we have a long, descriptive sentence, that describes in detail a type of flower along Myop's path. The story is filled with such calm, happy descriptions. Contrast that with the final line of the story: "And the summer was over." The stark contrast is startling, noticable and points out the import of the message: Summer, happiness, and Myop's meandering innocence was over, and very abruptly.
Another tool that Walker uses is symbolism. Note that Alice Walker doesn't say "And Myop lost her innocence and realized what a horrible place the world can be" at the end. What she DOES say is that "the summer was over." Summer, in the story, symbolizes the innocence of childhood. So do the flowers; right before "the summer was over" comes the line, "Myop laid down her flowers," which symbolizes Myop setting aside her innocence and happiness. As she walks through the forest earlier, she gathers a lot of flowers; her arms were filled with them. They were various and beautiful, as described in the line above. So too was her happiness and innocence. But at the recognition of evil in the world, that innocence was no longer possible. Walker symbolizes that through the flowers and the summer.
I hope that those thoughts help to get you started; good luck!