Most patches sold in stores are iron-on patches, meaning they have a heat activated adhesive on the back on them that allows you to attach the patch without the use of a sewing machine. Sew-on patches, though less convenient, are permanently adhered to whatever fabric item you place them on, and therefore last much longer than their iron-on counterparts. Make your own sew-on patches to embellish any number of fabric pieces.
Cut apart the different parts of the patch design. For example, if you were making a cupcake patch you would cut the cup from the top of the cupcake because those two pieces would be cut from different fabrics.
Use each piece of the design as a template for cutting that piece from the fabric you want it to be made of on the patch. Also cut a piece of double-sided fusible web for each piece of the design as well.
Fuse each piece of double-sided fusible web to the wrong side of its corresponding fabric piece using an iron. Consult the instructions that came with the brand of fusible web you are using for correct iron heat settings and ironing times.
Put together the different fabric pieces of the patch design together on top of the muslin. Put the pieces together so that their edges butt up against one another.
Iron over the design to adhere them to the muslin once you are happy with their arrangement. This will activate the other side of the double-sided fusible web, fusing the different parts of the design to the muslin.
Use a narrow zigzag stitch to sew around the outline of each individual piece of the design to both permanently adhere it to the muslin as well as to connect the different pieces of the design.
Cut out the design from the rest of the muslin to complete your sew-on patch.
Simple designs that don't have small pieces are best for the first couple times you make your own patch. Plain woven cotton materials, such as quilter's cotton, is easiest to work with when assembling your own patch. Use online colouring pages for patch designs. Use tracing paper to trace a design you want to use for a patch to avoid cutting the original. Trace the design onto the paper and then cut apart the traced design rather than the original. The number of different fabrics, the amount of each as well as the amount of muslin you need will all depend on the design you choose for the patch. Make a simple sew-on patch by cutting a one-piece design from printed fabric and adhering it to muslin. Stitch around the edge of the design with a narrow zigzag stitch and cut it out for a completed patch.