Create a comprehensive art lesson plan that focuses on Color Harmony and Watercolor Techniques, ensuring students can demonstrate a cohesive color palette for a landscape painting. The learning objective is for high school students to master the principles of color harmony and apply various watercolor techniques to create visually appealing landscapes. Incorporate watercolor paper, brushes, and a variety of watercolor paints as materials/equipment. Allocate a two-hour time frame for the lesson. Encourage student engagement through a collaborative color-mixing exercise, allowing students to explore different harmonious combinations. Assessment will be based on the final landscape paintings, evaluating color harmony, technique proficiency, and overall creativity.