Ack!!! The dreaded 1/4" seam....I think every quilter has had that problem especially when they first start to quilt. One thing you can do is get a cutting ruller that has a 1/4" marking on it close to the edge of the ruler. Place the 1/4" mark line under your presser foot and line up you needle exactly to the line. Now take a piece of painters tape or masking tape and tape beside the edge of the ruler marking the 1/4" line on your machine. Mark it down away from your presser foot though so it doesn't interfere with your feed dogs. Now try to keep your fabric on the edge of the tape assuring you a good 1/4" seam. You can test it with a piece of scrap fabric to make sure it is lined up right.