Secondly reading and listening needs practice. You can use barrons or cambridge whatever you feel is approprite for you.
Writing just dont make spelling mistakes and also try to use different words.
Speaking Important try to close out whatever you are saying. Use something like in my opinion there should be more liabraries as it encourages reading habits of the society or i believe
Basic English matters a lot, the base which you developed in your school time.
At this time we can just polish few skills, but can not develop new skills.