First of all, let's ask ourselves: what does it mean to LEARN English? Is it possible to know the language perfectly?
You will not believe, but the same thing happens when you start learning other languages. It is not a secret that people around the world does not know any language PERFECTLY. Of course language levels are certainly exist. Thus, an elementary school student and a doctor of philological sciences would know their language differently. Before starting to learn a new language, you should answer the question "why do you want to do this?"
1 Why do I need to know this or that language?
- Whether it's traveling or moving to another country;
- New job;
- Watching your favorite movies and reading books in the original.
These goals should be as specific as possible.
2 What do I need to know to achieve my goal? You can determine your starting level on all kinds of educational sites or from a qualified specialist. Just try to Google "Language Level Tests" and you definitely will find something useful. Without a doubt, in order to go on a trip, it is enough to speak the language at a low level. The native speaker will understand you even without the knowledge of complex speech patterns. If your goal is to work abroad, then the requirements for the language level would be much higher.
3 How much should I practice? Daily practice is essential when it comes to learning. Routine and repetition make your practices stick in the long run. Many beginning students will start with 10-15 minutes a day because it isn't a massive commitment.
4 At this moment, we have determined why we want to learn, what we need to know and how much should we practice. The last but not least is to find a relevant source where we would take the information for our studying. 
In conclusion, I would like to say that to learn more productive, you need to allow the language be a part of your life. That's it, accustom yourself to the fact that a foreign language is the same as your native one. This can be done, by switching your phone into the language you intend to learn. You can also subscribe to foreign blogs and publics on social networks. Thus, you will get used it and it will become easier to understand.