Here's one tip that has worked for me in IELTS Speaking.
Before leaving home for the exam, I recite some tongue twisters just to help me avoid mispronouncing the words when I answer the examiner's questions. I usually visit a website for this. It's called Twister King. There, you'll see lots of practice exercises for each letter of the alphabet.
Say, you need to practice pronouncing the F, P, and TH sounds. Simply proceed to the relevant page, then practice. Here are some of my favorites:
Re: F
"Four free-flow pipes flow freely."
Re: P
"Pick a partner and practice passing, for if you pass proficiently, perhaps you'll play professionally."
Re: TH
"Tim, the thin twin tinsmith."
Keep in mind that in the IELTS speaking test, one criteria checked by your examiners is pronunciation. In other words, to get high scores when it comes to pronunciation, IELTS candidates should always pronounce words in the correct manner. You don't need to spend a whole hour for the tongue twister exercises. Even a few minutes would be enough to warm you up. However, if you decide to make it an everyday habit to recite an exercise or two, then good for you. You'll be on your way to improving your performance in the exam.
Hat tip to Twister King, for sharing these helpful exercises. Head on over to the site to improve your pronunciation for the IELTS exam.