This is an interesting article and tips:

If you look at the IELTS speaking marking criteria,
you will notice that pronunciation makes up 25% of the total marks. In
other words, it is difficult get a high band score in your speaking test
without good pronunciation.

Many students believe that good pronunciation is the same as having a
‘native English accent’. This is one of the most common misconceptions
and students should not worry about having a British or American accent.

Read more: http://ieltsadvantage.com/2015/03/19/helping-ielts-students-practice-phonetics-at-home-for-free/

I also came across with this article: https://aceyourielts.wordpress.com/2014/12/09/top-10-myths-about-ielts/