The pronunciation is maybe the one of the most difficult things which you have to learn in English. To adopt a good accent, you have to practise! It’s the secret. But to keep a little your native accent is not a shame.
3 tricks to improve your pronunciation:
#1: LISTEN ENGLISH
You can listen to videos, musics, series… it is just necessary whether it is in English of course. Choose a theme which you like or a series which you like, documentaries, etc. You will find what you need on the internet, especially on YouTube.
Listen English everyday is a good thing so that your brain becomes used to tones.
#2: PRACTISE ENGLISH
There are a lot of solutions to arrive there.
You can go in an English country for example, is the best thing. You can also go on CouchSurfing.com, who is a site of hosting of people at home. You are not obliged to accommodate somebody at your home or to go to somebody else; there are also events which are organized in which one you can participate. There are also websites on which you can practise English. Go to meet people who speak English or have a dialogue with them on the Internet. You can quickly progress!
#3: YOU PROGRESS BY CORRECTING YOUR MISTAKES
It is normal to make mistakes, we progress by correcting our mistakes. It is a good way to retain the mistakes has not to make. To try it is the most important thing, to make mistakes is not a shame: 20 % of your mistakes allow you to improve 80 % of your English. Be not hurt if we make you a remark, and try to correct you.
from IMPROVE YOUR PRONUNCIATION IN ENGLISH | THE BIS LONDON