You must evaluate the thread count (TC) and yarn count (e.g., 40s, 60s), as these determine the fabric's density and softness. For high-quality apparel, a yarn count of 60s or higher is preferred. Additionally, verify the fabric weight (GSM - Grams per Square Meter) to ensure it matches your application; for example, 150-200 GSM is ideal for sturdy shirts, while lighter weights are better for summer wear. Always request the shrinkage rate, which should ideally be under 3% for pre-shrunk high-end cotton.