One possible version:

Dear Li Wei,

     I'm sorry to hear that you're under great pressure. But in my opinion, it's natural that you are loaded with

lots of schoolwork and are doing many activities because you're a Senior Two student.

     I think the first thing you should do is to take control of your life. Make a long-term and a short-term plan

and put "must-do" jobs on a schedule. Set time limits to your work, which will help you develop a strong sense

of time. You can also benefit from making full use of your spare time. Listening to English materials, memorizing

words and expressions and appreciating a poem are all good choices. After studying for hours on end, try to

participate in physical activities to relax. Listening to your favorite songs will reduce your anxieties. A sound

sleep can increase your energy level and you will be more energetic. Last but not least, be confident in yourself

and be optimistic about your future and you will be able to manage your time well.

     Good luck!

                                                                                                                                             Yours truly,

                                                                                                                                             John