Start with a simple curved line for the cap of the mushroom. A rounded triangle shape is great for the top of the mushroom.

For the stem shape, draw a U shape from the underside of the mushroom cap. This creates a more rounded stem of the mushroom.

The next step is to draw a simple half circle at the edge of the mushroom cap.

Draw another half circle off the other side of the mushroom cap.

Draw two more smaller half circles in the other two edges.

Outline the basic form of the mushroom with a black pen on the final lines and erase any extra lines you had while sketching the simple mushroom drawings.

The last step is to treat your mushroom drawing as a coloring page and color it in with your favorite crayons, colored pencils, markers, or even watercolor paint. Viola, you have a simple mushroom drawing.