Practice, practice, practice.
Since I replied last time, I've applied the "practice" principal. Since all lenses were manual focus when I started the endeavor of photography, I was appalled at how rusty I had become and how dependent I was on AF. I've been using manual lenses a lot over the past few months and my focusing skills have been returning. Other than becoming familiar with the image on the screen, becoming familiar with how the "in focus" green dot behaves was also helpful.
In situations where I know there will be moving subjects or unknown circumstances, I still rely on AF lenses. But for my normal static subject matter, manual focus is enjoyable and rewarding.
Standard dog photo, manually focused with a 50mm at ƒ/2.8: