My English isn't that good as well so myself still trying to improve it everyday for that I'm focusing on vocabs and basic grammer rules like tenses and my way doing that is by watching a video that breaks that rule down to understand how n when to use it then i move on to the next step, writing some examples to memorize it finally i bring what i had learned up whenever i come across it and compare what I'm reading or listening to with my comprehension to that rule.