Here are some idiomatic expressions that can enhance your English language skills for the IELTS

1. “Break a leg” – Good luck!
2. “Hit the nail on the head” – Say or do something exactly right.
3. “A piece of cake” – Something that is very easy.
4. “Let the cat out of the bag” – Reveal a secret.
5. “Bite the bullet” – Face a difficult or unpleasant situation with courage.
6. “Kill two birds with one stone” – Achieve two things at the same time.
7. “Cost an arm and a leg” – Be very expensive.
8. “Once in a blue moon” – Something that happens very rarely.
9. “The ball is in your court” – It is your turn to take action or make a decision.
10. “Break the ice” – To initiate or start a conversation or interaction.
11. “A dime a dozen” – Something that is common and easily available.
12. “Ace in the hole” – A hidden advantage or secret resource.
13. “Barking up the wrong tree” – Looking in the wrong place or accusing the wrong person.
14. “By the skin of my teeth” – Just barely managing to do something.
15. “Fit as a fiddle” – In good physical health.
16. “On cloud nine” – Feeling extreme happiness or joy.
17. “Paint the town red” – To go out and have a great time, often by partying or celebrating.
18. “Under the weather” – Feeling unwell or sick.
19. “The apple of my eye” – Someone or something that is treasured or loved deeply.
20. “A blessing in disguise” – Something that initially seems unfortunate but results in a positive outcome.

Remember to use these idioms appropriately in context to demonstrate your language proficiency during the IELTS exam. Best of luck with your preparation!