When sourcing wholesale fabric, you must prioritize material composition, weight (GSM), and weave structure. For garment production, ensure the fabric weight (Grams per Square Meter) aligns with the intended use (e.g., 150-180 GSM for t-shirts, 300+ GSM for hoodies). Request colorfastness test reports (ISO 105-B02) to ensure the dye does not bleed or fade. Additionally, verify the shrinkage rate, which should ideally be less than 3-5% for high-quality knits and wovens to prevent sizing issues after the first wash.