Hi: you just have to make a lot of exercise. A good one is "Reverse translation": take an English-to-(Your language) translated text and translate it back to English: now check your mistakes. Do it many times. The second part of this exercise is "Listening comprehension": take an audio text in English, write it down and translate it in your language: now compare your translation. If you need this kind of material, you can search for translated lyrics(so you also have audio) and translated fairy-tales.

Well, if you identify your mistakes, then you can fix them. If you want to stop repeating your mistakes, then find the correct examples and write and say them repeatedly. It's a matter of forming a good habit. If you're not sure whether you are making more mistakes, then of course talk to someone (eg. an advanced or native speaker of English) and ask them. Aim for "correct and natural", and don't settle for "understandable".

Watch more movies in English , it will help you ! another method i used to learn 2 languages and become fluent is talking to myself, i imagine myself in a descussion and try to answer , if i don't find a word i google it , and then again make a sentence and check if it's right, it takes time but you'll learn the right way!

in learning we all make mistakes, but the important thing is correction, then next time you'll avoid the same mistakes.

Mistakes are good. We learn from mistakes. The greatest error a person can make is to not try for fear of making a mistake.