I have been working exclusively on this for years now and I think it's important that students know what the examiners what to hear. Most kids go to the exam and think that there are right and wrong answers to the questions. They think they should simply answer the questions. The examiner doesn't want to be educated about their hometowns, their families or their favorite foods. The examiner wants to see.....or should I say, hear, the level of the students English skill.  The strategy that works is an overall training program that includes a thorough education of the "marking system" of the IELTS exam. The students must think of this exam differently. There is too much to get into it here. I will try to find the link to the textbook I use. When I do, I will add it to this post. Basically examiners are there to give the student a score for their English ability.....not their answers. Tell your kids to not answer too directly. Tell them to use some redundant language, lead in phrases and topic related vocabulary. That, in itself should be helpful.

I love teaching IELTs classes and get so much satisfaction from my students when I see progress.