Hello,

See, in order to have a good command over language, it's important to be acquainted with its basics, if you already have a good hold over grammar and the only barrier is feeling confident, then practice it more and more, try to start with your family and friends, reading novels and watching movies, various educational channels in youtube will make you a lot more confident. There's an app in playstore called cake, it's a very good one and helps you improve your diction, so you can try that,it evaluates you how you speak well, so in a way acts like a parameter.