答案：Dear Li Jun,
How's it going? I'm writing to give you some advice on improving your English.
Firstly, be interested in what you learn. Our brain will be more active and you'll learn better. You can listen to English songs. Secondly, keep practicing every day. It helps memorize things better. Why not keep diaries daily? Finally, communicate with a partner. It makes you better at using the language. You could speak to a friend online.
I hope my advice can help you make progress in English learning.
Yours,
Peter