Writing skill should be taught across curriculums and should be encouraged in each course level the student progresses to.  In addition it is good practice to tailor the criticsms so that each student can have 2 or 3 areas to work on and improve.  It is also essential to make sure there is positive feedback to encourage student progress

I have learned that it is esseential to teach critical thinking to my students and to foster an environment that allows that process to develop