Any IELTS teacher's training you attend covers techniques on how to educate students about the exam. You learn more about the format and contents of the exam and specific pedagogical tips about how to help students best prepare for it. Training courses also give teachers a better understanding of how the course is scored.
Only a few institutions provide IELTS teacher training courses. The British Council offers trainings in locations around the world, and so do various English academies and schools. For example, the Sea English Academy offers IELTS training. It has locations around the globe as well.
The IELTS website also offers free, in-depth resources for teachers on its website. This site is good for self-guided studying. Downloadable files include past exams, detailed worksheets and information about the structure of the exam. The resources are divided into speaking, reading, writing, general and academic sections.
Paul Griffiths is an English teacher who has posted helpful resources for free on his website for IELTS teachers. His site includes teaching ideas and material specific to teaching students the IELTS exam. His information is based on personal experience as a teacher.