Prepare your garment buy pre-washing and drying it in your machine washer and dryer. Remember to check the tag for care instructions. If you aren’t supposed to put it in the dryer, then by all means, hang it up to dry.
You can opt to pre-soak your clothes in vinegar or soda ash solution to help the coffee stick to the fibers. Add a cup of vinegar/soda ash to a tub of water and let soak for at least an hour. What you use to presoak depends on what you are dying. For animal fibers [list of animal fibers] and nylon, use vinegar. For plant fibers [list of plant fibers] and silk, use soda ash.
Pour the hot coffee into the tub. Once you are all set, we can learn how long to soak the fabric.