For me the most important "drill" is counting my strokes and timing my intervals.If my speed goes up and my SPL doesn't(or my SPL goes down and my time stays the same) I know I'm doing something right.I have about 20 different breaststroke drills I do early in the season to focus on different aspects of the stroke.As the season progresses I do drills if I think something needs work or doesn't feel right.I do a fair amount of fist swimming in warmup to work on feel for the water(and EVF.) I also do dog paddle with snorkle in warmup to work on EVF.
For me the most important "drill" is counting my strokes and timing my intervals.If my speed goes up and my SPL doesn't(or my SPL goes down and my time stays the same) I know I'm doing something right.I have about 20 different breaststroke drills I do early in the season to focus on different aspects of the stroke.As the season progresses I do drills if I think something needs work or doesn't feel right.I do a fair amount of fist swimming in warmup to work on feel for the water(and EVF.) I also do dog paddle with snorkle in warmup to work on EVF.