I taught English for 5 years in Japan (even though completely unqualified... cough... cough...). In my last year I did something very similar. The thing that got me to change was that I started tracking how much time I spent 1-1 with each of my students. If you are lecture focussed, you end up spending mere minutes a year actually interacting with an individual student. I remember setting myself a goal of spending 10 minutes with each student every term (still woefully insufficient!!!) and realizing that it was impossible unless I radically changed the class structure.

I actually moved the assessment/quiz to the beginning of the class as a "review", followed by 5 minutes of questions. This allowed students to gauge how they were doing cold "out of the gate". Often the students would realize that they were having a problem and we would expand this section before we moved on. In a survey that I made of the students, this was actually the most popular part of the class (which surprised me initially).

Next, I did 5 minutes of "lecture". Keeping it to 5 minutes was almost impossible, but I got better over time. Then I did "circling". This is a technique where you make grammar constructions more visible through questioning. For example, "John is a brown dog", "Who is a brown dog?", "What is John?", "What colour is John?", "What kind of animal is John?", "Is John a goldfish?". I do a random walk through the students and make sure that everyone understands the day's concept. (For some reason I can't find a good link with a description of circling. It is originally a technique from TPRS if anyone is interested to search for themselves).

Finally, there is group practice. Essentially I made the students solve logic puzzles in English (I disguised them as "games", but it boils down to this). They were allowed to use any resource they wanted to in order to answer the questions (including asking me, asking their friends, looking up things in dictionaries, etc). I did not enforce an "English only" policy because these were very low level students who had self esteem issues, but I had a sheet with everybody's name on it and every time I heard someone use English to ask/answer a question I would give them bonus marks. This was essentially their "classroom participation" mark.

Another successful idea for the group work at the beginning of the year was to have a series of difficult questions. The students then had to write down the name of somebody in the class who knew the answer to the question (The game was called "find someone who knows"). The idea was to integrate the higher level students and make them a valuable resource for the lower level students. Generally speaking, the high level students usually want to impress, so they do things like answer all the questions put to them in English. This worked surprisingly well (though probably partly due to peculiarities with Japanese social systems).

I only got to touch the surface of this before my contract ran out. I decided to go back to being a programmer rather than pursue a career of teaching, but it was an eye opening experience. I couldn't believe the difference it made to stop concentrating on presenting material and start concentrating on my students. So instead of explaining things, I simply watched them try to figure it out for themselves, giving them advice from time to time.