The first part of improving your English pronunciation is realizing what you’re doing wrong, but once you learn how to say something correctly, you need to practice often, and for at least 30 minutes a day, repeating the correct way to say the problem letter or sound. This is when noticing how the words were actually formed with the mouth comes in handy, because if you are simply saying the sound without understanding its formation, then you’ll run into more problems down the road. When learning English, make sure to not skip the grammar, and this article on daily grammar practice will show you the best ways to do keep up with it.