Ask HN: How to improve communication skills for interview?

I am non native speaker. I am living in different country where English is not native language. But for interviews and all other official work english is mandatory and It is really required to crack the interviews and all.

My communication skills is not up to the mark and I am not fluent speaker. Because of this I am lagging behind from my fellow developers.

Please help and give some advice. How to improve communication skills. What helped you to learn english and become fluent speaker.

Thanks for your help