As a manager, here are the two pieces of advice I'd pass on:
1. We don't use passive voice in our memos. College is wrong. I've been out of college for a long time, but I always want to write to the business writing prof I had and let him know. We stress active voice.
2. I picked this up from a Murawski course (which deals with active voice writing). It was, "Doing work is bringing your supervisor a solution, not problems." That is, me going to my boss and saying, "Hey, I've got a problem here," isn't doing work. The work is going to my boss and bringing him or her a solution to the problem. Now, sometimes you get stuck and need help, and that's fine, and I'm happy to help - but your goal as an employee should be to bring me proposed solutions to problems (or, better yet, just take care of it, if you can).