One possible version:

My dear teacher,

I have been in senior high school for a month. After I enter senior high, I plan to set new goals in my study and improve my way of learning. What’s more, as I am away from my parents, it is necessary for me to learn to live on my own, such as doing some washing and cleaning by myself. In my spare time, I’ll take part in different school activities, for example, I’ll often go to the English Corner to practice my spoken English. In addition, I need to get along well with my classmates and teachers. I think I will have a wonderful life in my new school.

Yours sincerely,

Li Hua

题目分析：本文是一篇书信应用文。文章给出了简单的汉语提示，要求学生能够连贯的将内容表达出来。成文时应注意：1.文章内容要齐全：（1）确定新的学习目标；（2）改进学习方法；（3）学会独立生活；（4）参加各种课外活动；（5）处理好与同学的关系。2.人称：采用第一人称；3.时态：将来时为主；4.恰当使用一些高级词汇、短语和句型；5.使用一些连词和插入语使文章表达自然，流畅。

【亮点说明】使用了插入语：What’s more, for example, In my spare time, In addition,等；使用了从句：After I enter senior high, I plan to set new goals in my study and improve my way of learning； as I am away from my parents, it is necessary for me to learn to live on my own；  I think I will have a wonderful life in my new school.