I think emphasis on one's individual perspective and enhancing their own style is important. While letting people be unique, I think it's still important to understand basics such as structure, shading, quality, etc. that can be seen in any style of art. I'm completely a self-taught artist, and have fed off of the critique/comments I've received throughout my life. A lot of it comes down to finally having that 'click' when something just makes sense and looks right ^u^ sometimes that comes fast for people, and for others it's much slower. I think patience with art is the most important
To add on, I read both that post and the one directed towards students.
Since I've been in college (not studying art) a lot of the things mentioned on both sides are relevant to any teacher. One thing that seems more specific to visual art (and maybe writing...) more than any other field in terms of teaching seems to be being able to see the way a student sees and tailor to their specific concerns and figure out their concerns before they even arise in the first place! I see that concept more with people who have completed schooling and are now are working with developing a product for clients.
The top teachers I have gotten the most out of are the humble, wise, extremely knowledgeable/experienced in the field, and super fun, but still lead with a stern hand. These are also teachers whom do not judge or argue against a student's thought process, but simply guide them through it and help the student the best way that is possible in regards to fulfilling the student's vision. These teachers/professors have also unloaded a double barrel too the head, and given harsh but extremely beneficial and motivating advice during critique, and most of all, wisdom that has usually been about their experiences in the professional field and what to expect/ is required of you. which in turn lead to cool life stories and a healthy dosage of informative growth as an art student. ^_^
It's a happy medium so to say, and it is rare to find such people, but it is something that comes with growing life experience and good people skills. With that said, let those whom seek advice/to learn from you, be welcomed, always, with a smile, open arms, and a truck load of advice/wisdom that the student might crave ever so much from a teacher.
An impressively decent level of artistic talent is a must I think; it's all well and good having all the teaching qualifications, but they mean little if one is not highly proficient in the subject being taught. Especially for an art teacher, I think being able to lead by example is a must.
I'm sure I could say a lot more, but I'm sure it's already been said here.