Forget about printing on some transfer paper and then ironing it onto some fabric. With some freezer paper you can print right on the fabric itself. No need to reverse the image and it's faster, cheaper, and more effective.
How to Use a Quilting Presser Foot: Stitch In the Ditch
Using a walking foot to stitch in the ditch You will be able to feel which side of the seam is high with your fingertip. The trick is to REMEMBER TO FEEL FOR IT before sewing the upcoming section of seam. Then stitch on the lower side as close as possible to where the fabrics are joined.