When evaluating denim quality, focus on fabric weight (measured in ounces); 8-10 oz is ideal for lightweight summer dresses, while 12-14 oz is standard for structured skirts. Ensure the material is pre-shrunk to prevent size distortion after the first wash. For stretch styles, look for a spandex/elastane content of 1-3% to ensure shape retention. Additionally, verify the wash process (e.g., enzyme wash, stone wash, or acid wash) to ensure chemical residues are neutralized and colorfastness meets ISO 105-C06 standards.