The best way is to just speak with native English speakers. The more you do that the better you will get.
That's very good advice. It's probably the fastest way to learn a second language. It helps to be able to think
in the language you are using, also. When you can do that, you're thinking in the language rather than just translating back and forth in your head. I took Spanish in school, but was never taught to think in the language. It therefore was difficult for me to pick up. The way a language is taught has a lot to do with how quickly a person picks it up.
Then too, English is a difficult language to learn because it's structure is so different from most romance languages (Spanish, Italian, Portugese, French and the like) not to mention other languages such as Russian, Middle European languages, Arabic, Chinese, and other southeast Asian languages.