Lovely runner! Cut and sew as accurately as you can and you will get better the more time you invest in quilting. In the meantime, enjoy the process . You can quilt using your regular foot but a walking foot does make it easier. If you are stitching in the ditch on your runner, lengthen the stitch length a bit and quilt from the middle out. Starting to quilt in the centre and working to the edge helps to move any extra fabric out to the edge so you don’t get wrinkles in the back.