Hi. There is no magic trick for improving your English. What you can do deeply depends on what you can already say and understand. Generally speaking, you should always try to do a full study. Reading, Listening, Speaking and Writing. If you don't do all of them it's like not studying at all 😀 Grammar comes along with them so you can study it by asking questions and reading articles whenever you need to understand something new you just encountered but don't neglect any part of a language. If you only do reading and listening, you will never be able to speak and write. There are plenty of people out there who can understand quite well but they can't open their mouth and express anything and I doubt that's what you want, right?
As the comment above me, Unfortunately It's impossible to learn it over a night. There's a chunk of fundamental aspect that you should be careful and consistent about. Language learning requires a lot of effort and time. First of all, You should know that from the beginning, You'll not be able to learn everything at once. Mindset is everything, Later You'll be consistent with what you do. You can't let your strike disappear. You'll do your best to keep in track. The most vital thing when It comes to learning languages is your mindset. It's the solely one either get you do it or not. Be attentive with that :)