Learning English and understanding how to improve your English skills is very good. Learning practicing how to pronounce and write in English is even better. Your goal is to be able to communicate in English so that others understand you, and that you understand them. Do you want to sound like an American? If so, I teach my students techniques how to create new habits of pronunciation to sound exactly like an American as if they were born and raised in the USA. The same techniques can be used to sound British too.