When sourcing designer fashion, focus on fabric composition and weight (GSM). For luxury apparel, prioritize natural fibers like mulberry silk, Egyptian cotton, or high-grade merino wool. Pay close attention to construction details such as French seams, hand-rolled hems, and pattern matching at the seams, which are hallmarks of premium quality. Ensure the hardware (zippers, buttons, clasps) is made of durable materials like YKK zippers or real horn/mother-of-pearl buttons to maintain brand integrity.