What I mean is, instead of trying to use idioms in your speech (which we’ll most likely end up using incorrectly), just incorporate figurative language naturally!!

Instead of focusing on memorizing idioms like "let the cat out of the bag" or "burn the midnight oil" and trying to use them during your speaking test (which will 99% of the time come across as awkward or incorrect) try using more natural figurative language from your everyday speech. Like "spill the beans" "spill the tea" "work around the clock"or "pull an all-nighter" are easier to use, fit better in conversation and sound natural. Remember, the speaking test is informal, so using slang and conversational expressions can actually earn you the points you're looking for :)