I thought it was time to point you in the direction of some of the previous articles from cpdfordanceteachers.com.
Feet are very important for dancers (and dance teachers) so I hope you will download the Focus on Feet exercises as well as reading the article and watching the short video about alignment of the Achilles.
Making corrections count is about giving your dancers the most important correction/s that will have the most useful outcome rather than giving lots of smaller corrections that may ignore the key, fundamental correction that, when corrected, would also resolve many of the smaller issues.
We should consider what the most important correction is that we can give rather than giving a whole bunch of corrections that are likely to be very transient rather than incorporated into practice in the longer term. In my PhD thesis I wrote the following: