English is very difficult to learn because there is no consistency in its sounds, grammar, and pronunciation. Even the same word has different meanings depending on its pronunciation, and can have different pronunciations depending on its meaning! An exaple would be the word "lead." It sounds like "leed" (and rhymes with "bead") if used as a verb, but sounds like "head" if it describes the metal. And why "lead," as in the metal, rhymes with "head," "bed," and "led" but "lead" (the verb) rhymes with "reed," "weed," and "bead" is crazy and takes a while to learn even for native speakers.

I lnow you're a Portuguese speaker, but if you understand Spanish at all, check out "Superholly" on YouTube and Instagram. She is bilingual and fluent in both English and Chicano Spanish, and has no trace of an accent in either (she is a native speaker of both). She has a video, in Spanish, that describes something like "11 mistakes Spanish speakers make when speaking english" that touches on pronunciation it might be helpful!

You can record your own pronunciations. And then you can listen to the correct pronunciation by using free dictionaries, Oxford, Merriam Webster and Cambridge.

You had better identify the exact reason of which you cannot pronounce English properly and precisely then target the weak point and find the solution to improve your pronunciation. 

Repeated learning is required to master pronunciation in a sense but many people have no basis on English pronunciation so repeated learning is not effective to them. In this case, they had better amend the weak point before they can make a significant progress in English pronunciation. 

To become fluent you need to speak

I am not agree with watching movies, I feel exhausted whilst watching bcz I can't undrestand them. Even with two subtitles. These are what I am using, italki, hinative, engvid. And also I am looking for a partner, would you like be my partner? Let's try it maybe it's useful