As far as comments go (especially for storybooks/writing portfolios), I'm used to giving constructive criticism but I wasn't sure how far I should go. I usually gave people a few tips on things they could change and then lightened up, but a lot of the comments that I got were just praise. I really love constructive criticism myself, but I know some people find it difficult so I wasn't really sure what would be appropriate. I think a little guidance in that area would be nice. In my graphic design class, we had to give "sandwich" advice. We'd say one thing we like, one thing they could change, and another thing we like. It may sound a bit "grade school," but I think that kind of format would help.
Looking back on the semester, I suggest that students who struggle with writing do a little reading for fun in their spare time. I would take note of sentences that I thought were well-formed or unique in some way and try to use that to inspire myself to do something interesting with my writing. Staying on top of the assignments in order to minimize stress also helps.
I would love to see myself doing more writing in the future. I have so many ideas in my head that I'd like to get down on paper (or "paper" since it would be on a computer), but I'm not sure if I'll have the time or even the confidence to approach it. But I'm going to try!