Hi, there..
I'm a non-native English speaker. The way I did it was to read a lot, about a lot, and do it out loud.
Also, whenever I watched TV shows/movies, I'd find myself repeating expressions after characters. I didn't do it consciously, it just happened.
What this does is expose your flaws as some words are challenging (because the muscle groups activated in English aren't necessarily the same as in other languages). You then rectify your pronunciation to get it right.
