I know that discussion questions are off-topic. But I would like to know a good way to learn new vocabulary. Tips and tricks that help to learn English.
Is there any proper way to ask such a question here?
The problem with "fishing for tips" is the inherently open nature of the question itself. This is a fundamentally broad topic that would fill entire shelves of a bookstore. I know it sounds strange for a Q&A site, but such "getting started" questions can only be discussed, not answered, per se.
Stack Exchange sites work much better when you ask really specific questions you encounter in your studies or day-to-day experiences — something that can be authoritatively and completely answered in the space of a post in this format; problem solved. Without that specific question, users are really just guessing what will actually help you, so just about anything folks care to contribute will be as "correct" as anything else offered as an answer. That goes fundamentally against how Stack Exchange is supposed to work, so that is why we forgo these types of questions.
It's a good question and a valuable part of learning, but these type of talking-point and discussion questions are better asked in a discussion forum or even our own chat rooms. It's an interesting questions; it's just not well-suited to this type of site.