Recently one of our ladies in class forgot to change her foot when she did her top quilting. You could actually see where the fabric had moved incorrectly causing puckers. Try using a walking foot but echoing not in the ditch. If you echo you can follow a seam with the side of the walking foot and not where the needle is. Also if you are doing straight lines don't forget to go up one way and down the opposite way .
You could put on your darning foot, I like to see the needle and one of my machines had a round darning foot which I altered by cutting out a small section at the front so I can see the needle. Then do free motion.