When selecting garden solar lights, prioritize monocrystalline silicon solar panels over polycrystalline ones, as they offer higher conversion efficiency (up to 22%). Ensure the battery capacity (mAh) is sufficient to power the LED for at least 8-10 hours after a full charge. For brightness, check the Lumen (lm) output: 5-10 lumens are suitable for path marking, while 100+ lumens are necessary for security or spotlighting. Additionally, verify the IP (Ingress Protection) rating; a minimum of IP65 is essential to ensure the product is waterproof and dustproof for outdoor durability.