I wonder why Li Fu didn't get an interview. My guess is that Thailand simply didn't need new examiners. There is way, way more work in China than in any other country in the world. There's a lot of examiners as well, but my feeling is that regions like to have too many rather than too few.
So, if you have the quals and experience, I'd have thought they'd definitely give you the phone interview, unless there's something dreadful in your application. I expect it was just the not needing examiners thing. Didn't they give you a reason?
From then on though, maybe it can get tough. I don't think passing the phone interview is a formality. It lasts half an hour. They wouldn't spend that much time if they were just checking that you could speak English.
Then you have the 2 day training and accreditation. People's best guesses are that only half pass that first time, though it can vary widely. You can keep taking it till you pass though, not that that would necessarily be a good idea.
Then you're in, although you're regularly monitored to check you're giving the correct scores.
I'm not sure there are any secrets. I found that the people who asked lots of questions during training, were the ones who passed. You'd have to guard against the assumption that you know it all because of your experience IELTS training. Based on IELTS trainers I've met, and the methods that some candidates think will work, I think that a lot of IELTS training, at least for the speaking exam, might be rubbish.
The IELTS books that students show me are rubbish. Candidates need to be prepared for the format of the exam. Other than that I think it's down to how good you are at English.
So, that's my one piece of advice. Don't assume you already know it all, or indeed anything. If you start telling Examiner Trainers in the interview how to pass the IELTS, there's a pretty good chance that you'll come across as an idiot.
Some people think that they deliberately weed out wankers. Certainly the incidence of this condition is much lower amongst examiners than it is in the general china ESL population, though I doubt anyone would claim it was extinct. Whether you're a good teacher is probably completely irrelevant to whether you're a good examiner. I think they're 2 largely different sets of skills. As for the con man thing, again examiners tend to be much more in touch with reality than a lot of the teachers and IELTS tutors I meet, but maybe being a good conman would be helpful as an IELTS tutor. They're essentially selling snake oil. Not useful for examiners.
This is all just my personal take. Other people have a lot more experience and knowledge.