I would suggest that you read a lot in English, and write down sentences that contain certain words or phrases that you find useful. By writing them down, you can check them later and use them for practice. You can also do this with words/phrases that you hear on television or on the radio. If you want to sound like a native speaker, you will need a lot of exposure to the language, and thanks to the internet, you will be able to find lots of material on the internet that will help you. (YouTube videos, webpages, radio stations, etc.) The most important thing is how you use the material to your advantage. Pay close attention to the situations in which certain rules or constructions are used and find out how you can learn from that so that you can apply it in different or similar situations. Circumstance and exposure are key. I hope that my advice is useful to you.

research, read, practice then apply :)

Excuse me, another mistake: "was a little vague"

Perhaps the phrase "circumstance and exposure are key" were a little vague. What I meant is that the most important things are circumstance, the amount of exposure, and how you use your learning material to your advantage.