There are four skills including speaking, listening, writing and reading.
For listening skill, you can improve this skill by watching English movies or listening to English songs. While you are listening or watching, you should use a dictionary to look new words up. And after that, you can learn by heart some dialogues or lyrics that you like best.
For speaking skill, you can listen and repeat a small dialogue that you watch on TV or on youtube, An other way, you can talk directly with foreigners who are traveling to your local.
For writing skill, you should know how to write a right sentence. You need to understand English grammar and structure and do grammar English exercise in a hard-working way.
For reading skill, you can read English newspapers, comics or short stories. While you are reading, you should guess the mean of the words that you don't understand. After that, you can look them up in dictionary to check what you guess. And then, you remember them and test yourself gagularly about your vocabulary.
To sum up, there are a lot of ways to improve your English. To get a good result when choose suitable ways and do them in the best way.Good luck!