The Internet Grammar of English (www.ucl.ac.uk/internet-grammar/) offers an online English course for free. It's English language course is very gradual, starting from the study of words, to word classes (major and minor), to phrases, then clauses, sentences, paragraphs, to forms and functions. The training course also has a great number of exercises on the different aspects of English grammar in varying levels of difficulty and complexity. It even provides a list of suggested further readings for better practice and higher English proficiency.

Having a competent level of English proficiency, or any language for that matter, brings numerous benefits and advantages more than you can imagine. It can bring you to farther places and open more paths for greater opportunities than you can ever think of. Just mere reading without application will not bring you anywhere. The world is moving so fast so you better catch up.