So, in the past I have been a little challenged with getting a perfect 1/4 inch seam when piecing quilts together. I would always end up with a wider seam and blocks that were too small. The 1/4 inch foot helps a lot. You can get one with a little guide on the side for most machines but I like to see the edge of my fabric.
When I finally broke down and took an official quilting class, our instructor, passed out little pieces of quarter inch tape used to mark quilting lines. She lined it up with our 1/4 inch foot to make a guide down the front of the machine. My bobbin cover has a little guide, too, to help line it up. The tape is low tack and won't gum up your machine. Easy, peasy.