One piece of advice is "What you focus on will increase." I think I am going to share this with my students because I do tell them to focus on the strengths in the work and the weaker elements will fall by the wayside in their drawings. I also note that without error the trial and error path to learning about new drawing tools and techniques won't work. There is no way to predict which tool or technique will blossom in the hands of exploring artists so I strongly support experimental work that does not achieve student expectations MORE than students playing it safe and sticking to a tried and true method they've developed over time.
When in the professional world students will have to adapt to group aesthetics and established look and feel guidelines, so exploring new ways of doing things (learning) is key to becoming a flexible and confident team member in the knowledge economy.