When sourcing custom footwear, you must prioritize material quality and construction techniques. For the upper, specify top-grain leather, high-performance synthetics, or eco-friendly recycled knits depending on your target market. Ensure the outsole material (e.g., TPU, Rubber, or EVA) matches the intended use—rubber for durability and grip, or EVA for lightweight cushioning. Additionally, confirm the lasting method (e.g., Strobel or Cemented) to ensure the shoe's structural integrity and flexibility meet your brand's standards.