I'm currently commuting to Seoul 3 times a week, studying at the British Council in Seoul for the Celta Course. It involves getting up outrageously early and making my way to the nearest KTX train to get on the 7:05 (am!) train. It's me and the sleeping/snoring businessmen mostly.
Anyway, so far it's been valuable in terms of learning lots of good stuff. It's definitely made me think about what I do in the classroom and why I do it. A few things I've appreciated:
1. The focus on meaning and form when teaching grammar. Without giving some meaning, or context for using the grammar, students won't remember or care. In the past, I've often been guilty of just teaching the forms but not doing enough with the other part.
2. And for vocab, there should be meaning/form/pronunciation in your explanation. I quite rarely focus on pronunciation of the words, but I plan to do this more in the future.
3. Grammar. Serious grammar. I never really considered myself a grammar slouch, but I'm definitely getting a lot more up to speed on common grammar forms in the English language. And learning about the different situations in which you'd use each one. I guess I haven't really taught that many advanced students so have never been challenged beyond the basic stuff. Most of the students I teach have enough issues with the simple present/simple past/past participle that we could spend an entire year just doing that.