One of "tools" that I was able to employ as a student when I started my open water training back in 1982 was the technique of visualization. My PDIC instructors conducted 6 - 8 class and pool sessions in the Fall. I was invited to come to every open water class that was conducted after mine to keep my skills sharp for the open water dives that were conducted in the summer.
Classes began Tuesday evenings and ran 3 to 3.5 hours. The first thing we did upon arrival in class was to view a 20 - 30 minute video related to the skills we would be doing in the pool and the information related to the diving science we would be covering in class. Next, we would go over the homework from the previous class and hear the lecture from our instructor which lasted about an hour including Q & A.
Finally, we would go into the pool, have class for about an hour and get 20 minutes of practice time on our own to work on weaknesses with our buddies.
On the days in between classes, I ha a week to read my Jeppesen Open Water Manual and a week to visualize all the skills that we had up until that point. During the process of visualization, I spent a good many hours each week thinking about the videos I had seen, thinking about our classroom discussion, and thinking about what I learned in the pool. While I may have only had about an hour and a half in the actual water each week, I'd probably spend that much time, if not much more, daydreaming about scuba class while in high school classes, thinking about it on the school bus ride home and in all my free time. I could go back in my mind to mistakes I had made and craft the scenario over again substituting the correct procedures for tank valve breathing, buddy-breathing by sharing a stage, performing buddy breathing BCD-assisted ascents, removing and replacing my cylinder and scuba unit, and other such procedures that required a little more finesse than just sharing an additional second stage or achieving neutral buoyancy.
In addition, we were expected to return to class and do things independently with proficiency. For example, our first pool class was snorkeling and our second was the first night with scuba. We were taught to float our tanks on over our heads without touching the bottom as if we were dressing in deep water. We wopuld have to manually inflate our horsecollar BCD's, float our tanks on over our heads, clear our snorkels away from the shoulder straps as we did so, blast our snorkels clear of water and connect all of your hoses, regs, etc., in the water by touch. We weren't coddled and more could be expected of us because we had the time to think about class between classes. It was hard. There were times I would come home frustrated that a skill like buddy breathing from a single regulator with no mask while swimming didn't go well because our ascent was poor or someone swallowed water and broke into an emergency ascent to escape the mishap. But, we went back in and did iot the next week and did it better or did it well because we were thinking about it between practices.
Skill development is the result of muscle memory in the myelin created by practice honed by great coaching. This is all benefitted by time. When it is said that divers cannot perform to the level of the "old salts" it is simply because no one is giving them the time to become good in the pool and in open water, because no one believes in them ("Open water diver's are capable of ..." Or, "At the open water level, they don't need to know ...")
To this day, as a 41 year-old cave and tech instructor, I still draw from those first experiences when it comes time to choke on water, vomit, or be without gas. When those things happen now, it takes me right back to my teen years. Ah, memories!
The mind is a terrible tool to waste.
Just as we teach students, "Slow is smooth. Smooth is fast," instructors, and more importantly training agencies, shops, resorts, and the RSTC, would do well to remember that the same applies to the learning process.