I have a couple of suggestions. My background is that I'm an engineer. I graduated about 40 years ago with my bachelor's degree.
Back in the day, our department had two "writing" courses: "Tech Paper 1" and "Tech Paper 2". Each was a single credit course, and in each course, the papers were due a little less than a month into the semester. For each paper, there were very strict rules. Each had to be less than 10 pages, double-spaced (back in the day when we used typewriters - I don't know how many words that might be).
The papers had describe a technical problem in the "Problem Statement" (aka Introduction) section. Then they had to propose two or more possible solutions to the problem - including data, feasibility, etc. Finally, there was a Solution section that explained why one of the possible solutions was chosen.
The papers also needed a clear, less than 100 word abstract.
I can see something similar being done with management students. The problem wouldn't necessarily be technical (it might be choices for a product launch, for example).
In those days, the department's standard grading ended up with <10% A grades, maybe a little less than 40% B. The rest were Cs, with a smattering of D grades.
The rules for tech papers were special. If the student got an A or a B on the first submission, then the course was finished (though B students could resubmit and try for an A). Otherwise, the student needed needed to take the comments on paper, incorporate them into a new submission and present that. An A or a B on the second try lead to an A or a B. Otherwise, there was the possibility of a third submission (I don't think A was possible at that point). I believe that the grading on the last submission was a bit tougher (for example, if you had a C and didn't noticeably improve the quality of the paper, you could possibly slip to a D (I think - it's been a long while)).
The idea was to get students writing like professionals, not like coddled high school students. The grader's comments were nearly all in the area of making the paper more concise and more focused (well, as well as improving grammar, spelling, etc.). The idea of multiple submissions was to make the student understand that his/her work would be reviewed out in the real world, and that re-work was pretty standard. The grader's expectations were said to be in the realm of what a supervisor's expectations would be once the student graduated.
There was some allowance made for students who were writing in a language that was not their primary language (and, in part because this was in a Canadian university, papers could be submitted in either English or French).
I thought then, and still think that this was a great way to get students to write clearly.
Since that time, I've been working in industry (with the occasional detour into graduate school). I've mentored several of my co-workers on their writing skills.
As other people have mentioned, the best way to learn to write is to read a lot. But, I go further and say that when you find something whose style you like, you should read it out loud, and listen to what you are saying when you do that.
Then, when you write, you should always read what you have written out loud. Listen to what it sounds like. See if you run out of breath before you finish a sentence. See if you can muddle through that 50-60 line paragraph without forgetting what the point was. When you read out loud, you will hear the fact that you included the same word in the last three sentences.
I'd like to think that having students read an excerpt of their work out loud to the class would be a good idea. However, that would be unfair to non-native speakers as well as those who really don't do well in public speaking. But, if you decide to pair students up to review each other's writing, having part of that review being done out loud might be a good idea.