Embroidering by hand is a tedious task any way you cut it. If you have access to an embroidery machine or work with someone who provides the service, you’re lucky. However, several cosplayers and people that sew do it stitch by stitch. Inu Dream Cosplay shared a tip that won’t necessarily make the process go faster, but it will give your embroidery some depth and make it easier to keep your stitches uniform. She draws the stencil onto the fabric and then traces it with 3D paint or puff paint. Once it dried on this particular costume (a replica of the Red Queen dress from the movie Mirror Mirror), she used a silver crochet thread to stitch over it. Each feather took about eight – nine hours to complete.
You could use this technique for any applique or designs you need to apply to your costumes. I think it could work on both fabric and armor.