In my opinion, spending time “working on turns” is wasteful when it just involves starting from mid-pool and “doing turns.” I prefer to do something more like the following set, intended for one of our freestylers who has been having a difficult time with getting the approach to the wall right.
9 x 100 @ 3:00 from dive
#1-3 80% effort (no higher) with maximum focus on approaching/attacking the wall, getting an excellent pushoff and streamline
#4-6 same as 1-3 but at 90% effort (only if #1-3 were completed satisfactorily)
#7-9 100 % effort, same level of excellence expected on turns. If #4-6 were not done well, these last three are still done at 90%