You can draw your design on paper (newsprint or Golden Threads quilting paper) and pin it to the fabric. Then you just stitch through the paper and remove it when you are finished.
Try out your ideas on a practice quilt sandwich before you actually start on the real thing. I cut squares about 9 x 9 to practice on. It takes about 20 minutes for your muscles to warm up. You can always use the practice pad as a potholder afterward. I have a lot of strange looking potholders LOL