Will you speak the English language well if you learn all English words and grammar rules?
The answer is no. This knowledge will be “dead” because you will not be able to apply them freely. Your aim is to use them in context. Without a text, your English words and rules will simply disappear in a vast, overgrown jungle, your memory.
In any case, a qualitative approach to English grammar studying is built on its gradual learning. Building the language base, grammar knowledge and introducing the new words and turns of speech at the same time will get you to the point where you perfect your language skills. Even simple forgetting which is typical for memory will lead people to lose all the learnt words, first and then, grammar. Having reached a more advanced language level you will not need to memorize and study grammar because you will already use fixed English forms.
Start studying the language learning how to define the structure of a sentence and word order, parts of speech, conjugation of English verbs, declension of nouns and pronouns. You shouldn’t forget about multiple exceptions to the rules. Learning these exceptions you will remember the rules at the level of association. Reading fiction helps you find analogies and exceptions which facilitates the process of grammar structures ‘memorization.
Self-made charts, cards on grammar rules and cribs will help you a lot because using them will make your visual and associative memory work. Apart from that, the majority of languages refer to the process of historical assimilation and they have many common features.