Plausibly the the best way to teach is to praise positive actions and rectify the negative ones and improve upon it. I would partially disagree with the above issue. In the following paragraph we will discuss about points due to which I partially disagree with prompt. We will also discuss about the the counter arguement one might present.
Firstly, If one ignore the negative actions like mistakes and the actions which are distracting them, they might not be able rectify and improve upon them. Lets take an example of a person who is preparing from the GRE exam. If the teacher do not rectify the problems he is repeatedly doing in the exam or things he/she is involved in which are making him distracted, them he very well might not be able to improve. If he/she is only praised about the positive things he is doing and not told to bother about the negatives ones, he will be at the same level after 2-3 months of preparation compared to when he started the preparation. Because he/she was never encouraged to see the negative action affecting his/her progress.
One might argue that ignoring the negatives actions of the learner and praising only the positive actions will help motivate the candidate more and if he is told about the negative ones he will be discouraged. Perhaps this may be partially true, however, the most important thing for the teacher to do, for improving upon the thing the candidate is doing wrong, is to help them identify the mistakes they are doing and motivate them to correct them instead of let them discouraged from it.
Therefore, considering the above arguements, the best possible way to tech would probably to indentify the negative actions and help improve it and correspondinglr prasing the positive action.