The document discusses key elements of design including lines, texture, color, and their relationships. It describes lines as providing structure and directing the eye, texture as the surface quality, and color as affecting appearance. It defines related colors as shades of one color or neighboring hues, and contrasting colors as opposites on the color wheel. The document also discusses principles of design such as proportion, balance, movement, emphasis, harmony, and their roles in achieving order and beauty. It provides examples of applying these design elements and principles to embroidery projects.