I've been quilting for a while and struggled with the skinny to fat to skinny 1/4'"seam. Recently I had an "AHA" moment. The sewing machine I use most of the time, has a "slow, medium, & fast speed". I love sewing fast but wasn't accurate. I decided to try the "medium". Wow! What a difference. I only watch the inside of my foot, never the needle.
I, also, did one other thing. I use a see through foot, that has plastic on the center and have moved my needle so that running the fabric under the right (harp) side edge of the foot, as I am sitting looking at the machine, produces a consistent 1/4" seam. It is the most accurate I have ever been.