The color and material of your bias tape will depend on the fabric and design of your project. You can choose a color that matches or contrasts with your fabric, and a material that complements the texture and weight of your fabric. For example, if you are working with a lightweight fabric, you may want to use a lightweight bias tape made of cotton or polyester. It's always a good idea to test a small piece of bias tape on your fabric to make sure it looks and feels right.