Practice, Practice, Practice.

While I was in NZ and away from the Longarm machine, to keep my hand in, I had to practice with pencil and paper.  Sketch after sketch.
In the quilting world, they commonly refer to this process as PPP. Even after only a relatively short time of practice, the feathering was noticeably improving.
The process of PPP, builds cell memory in the brain, and then when attempted on the machine, has similar results to where the level of your sketching quality is at.