When evaluating single jersey, the most critical factors are GSM (Grams per Square Meter), fiber composition, and yarn count. For standard T-shirts, a weight of 140-180 GSM is typical, while lightweight summer garments may require 120 GSM. Ensure the composition (e.g., 100% Cotton, Cotton/Spandex blend, or Polyester/Cotton) aligns with your target market's needs for breathability and elasticity. Additionally, verify the yarn count (e.g., 30s or 40s); higher numbers indicate a finer, smoother fabric surface.