When sourcing designer-grade clothing, focus on fabric composition and weight (GSM). For premium t-shirts, look for 100% Combed Cotton or Pima Cotton with a weight of 200-250 GSM. For suits or outerwear, verify the wool super count (e.g., Super 100s to 150s). Pay close attention to construction details such as double-needle stitching, reinforced seams, and the quality of hardware like YKK zippers or genuine horn buttons. Ensure the colorfastness rating is Grade 4 or higher to prevent fading after multiple washes.