Many IELTS and ESL teachers tell you to use idioms to sound more like a native speaker. This is good advice but a lot of the idioms that they teach you are old-fashioned and rarely used by native speakers e.g. It's raining cats and dogs. As a native speaker, I have never ever used this phrase in my life. I would say: It's chucking it down. Watch our IELTS Speaking Part 1 video to see how a native speaker would use some complex phrases for answering some Part 1 questions about things that you like.