The best way to read in English is to read by context. For example, if you have a paragraph read it the first time from start to finish without stopping to find the meanings of new words. Read it a second time but now underline the words/expressions that you don't understand. Try and use your brain to guess the meaning of the words/expressions. Ask yourself: "What kind of meaning does this word have in relation to the words around it?" Be logical. The third time, if you really don't understand the meanings of these words then consult your dictionary. Also the type of writing that you read will help you to understand it. Is it academic? Is it telling a story? Is it describing how to do something? I hope this was helpful for you.

You'll absorb the rules naturally as a result of more exposure. I'd say don't bog yourself down with these details, but that's just me. Good luck with your studies.

what do you mean? like speak it or gramatically?