When evaluating quality, focus on the leaf appearance, aroma, and infusion color. High-quality loose leaf tea should consist of whole or large broken leaves rather than dust or fannings. For green teas, look for a vibrant green hue; for black teas, look for golden tips. The aroma should be distinct and natural, without any chemical or musty undertones. Additionally, check the moisture content, which should ideally be between 3% and 7% to prevent mold while ensuring the leaves don't crumble into powder.