May I ask why you would want to? I understand the desire to speak English fluently and clearly. But your accent is a beautiful part of yourself. You may not want to lose it entirely! There is a big difference between heavily accented (hard to understand, hard to relate to) and someone who has a foreign lilt to their speech. Many English speakers will find an authentic accent charming. Keep in mind, too, that among English speakers there are many different accents. Even within one English-speaking nation, we vary greatly by region.
The best way to improve your speech is with a professional or community tutor who will listen for the difference between speech which needs to be corrected so that you are speaking clearly and that which does not and who will work to train your ears and your speaking to the way the language is used.
In my opinion, your first priority should be to reach a C1 (advanced) level of English. This process is likely to improve your pronunciation naturally because it involves so much exposure to the language. At that point, you could reconsider your desire and/or need to speak with a certain accent.
In my experience, only a small proportion of advanced speakers of English have an accent which closely resembles a native one, and many of those people live in English-speaking countries.
woooww!!! thank you so much for your comments.
now I know, I can open my mind what should I do firstly.