How can we promote better writing skills in academic education? This question may be too wide or in some perspective perceived as unclear but covers a key issue (for me) in academia, namely, academic writing.

Students start their academic career with varying skills in writing. Often, and this the case in my department, there is no thought through progression to go from beginner through novice and proficient to expert level (the latter perhaps in graduate school) or some such scale. 

My question is therefore how to get students to progress in appropriate steps through an education. In other words what is a reasonable progression of writing skills through an education. I am looking for suggestions of appropriate expectations for, say, an annual or semester wise increase in difficulty or complexity of exercises with the aim of learning academic writing skills through an education including graduate school.
In my lab, we were required to produce three-to-four page white papers, including figures, every time we presented at a lab meeting (approx. every 6 weeks).

This had two significant effects. Firstly, it forced the student to write down their progress, which was invariably ridiculously useful when the student actually started writing their thesis. Staple together a few of these sections and the methods, and often a good part of the background, was written for you.

Secondly, it gave everyone a chance to practice their professional writing in a casual lab setting. No one felt threatened and everyone improved. We would even review the articles being written by the lab professor, as there were always improvements we could suggest to him as well.

I strongly recommend this practice.