I made a label once just by setting my machine up for free motion quilting and then, so I would be able to do continuous writing, wrote/sewed in cursive. I realized that trying to do block style letters would be a royal pain.
Before attaching the sashing, iron the sashing onto the shiny side of freezer paper. Or use any stabilizer of your choice. I've heard of people using washaway stabilizer. Practice and see if you like how it looks. Mine looked just like handwriting.