Buy fabric medium (also known as a textile medium)and mix it with the acrylic paints you have at home make this medium will make your designs wash proof and keep your colours bright and vibrant. Your design will pop and sparkle for many many washes for years to come. Simply mix 10% with your acrylic paint. Now you are ready to paint your design onto your desired fabric. When creating hand-painted designs natural materials work best 100% natural fibres; having said that you can use synthetic its an excellent idea to do a test first to confirm.