Peter Gratton has a response up to my post on the CHE articles (he also should be winning an award for best use of my name).
He is absolutely right that for the most part that one learns by doing, especially with teaching. But, as he admits, there are things we can do to also better support our teachers, especially the TAs. I'm just thinking out loud here about some things I think that would be relatively cheap for the university and important for new teachers.
(1) A guide for navigating the institutional resources that your university has on hand. For example, you have a student you expect of a learning disability, what do you do? What tutoring is available, both for students with LD and other students? What different kinds of tutoring exists? You need to a reserve a classroom for some reason, how do you do this? You need a piece of equipment not in the room you are using, where do you go? There is a scheduling error with your course, who do you contact? And etc. (these were all chosen from personal experience, most of them occurring for the first time in the first semester of teaching).
(2) Assign mentors. Most pre-collegiate schools assign mentors to new teachers. A similar system would be very helpful for new TAs. The way I answered most of the questions above, is the first course I taught I had taken over from a grad student who was still around, and so I just asked him. Now, sometimes he didn't give me perfect advise, but I cannot imagine the nightmare if he hadn't been around. So, assign an older more experienced TA to mentor new TAs, one hopes the mentor even taught or is still teaching the course the new TA is teaching. Also assign a faculty mentor. Now, most new TAs will devise these systems themselves, informally. I cannot tell you how many discussions at the bar I have had with other grad students about teaching issues. But it strikes me that a formal system is probably helpful, as well.
(3) Formal evaluations and help. It is true that one learns to teach by doing, but like most of those practices, coaching helps (I should remind people that I probably have a more significant background in coaching, than I do in educating). There was a scene in the CHE series where a professor evaluates the author's teaching. She writes a scathing letter, and when she calls him in to talk about it, he basically just shrugs. Now, obviously both behaviors are absurd. If a professor calls you in, and you are having problems, rather than shrug, maybe try to turn that into a productive conservation about what you should be doing. But also, if you see a new TA failing, reach out and help. Evaluations should include discussions about what was effective, what was not effective, how to implement things in the future.
Anyway, nothing we do will prepare new teachers, of course not. But the current situation for most TAs at most universities seem inexcusable. I didn't have a horrible time teaching (well, my first semester was a nightmare, but that had to deal with a lot of issues, it being my first semester teaching not even being in the top five), but I also think there are fairly practical steps we could take to make the new TAs life slightly more bearable.