写关于姐姐的英语作文时，可以从以下几个方面入手：

个人基本信息

姐姐的名字、年龄、外貌特征（如头发颜色、眼睛大小、耳朵大小等）。

性格特点

姐姐的性格（如安静、可爱、热情等）。

兴趣爱好

姐姐的兴趣爱好（如弹钢琴、游泳、音乐、绘画等）。

特殊才能或成就

姐姐在某一方面的特殊才能或成就（如弹钢琴的技巧、英语成绩优异等）。

生活趣事

与姐姐相关的有趣生活故事或经历（如一次游泳的尴尬经历等）。

对姐姐的情感

你对姐姐的感情（如骄傲、喜欢、尊敬等）。

My Sister

I have a wonderful sister. Her name is Lily and she is 15 years old. She has long black hair and always ties it up. Lily has a special talent for playing the piano. She started learning it when she was just five years old and now she can play beautifully. She loves playing the piano and practices every day.

Lily is quiet and cute. She has small eyes, big ears, and a big nose. She speaks Chinese very well and also enjoys listening to music and painting. Last summer, she went swimming every day, but one day she had a little accident. She forgot her locker key and couldn't open it. After spending about half an hour trying, she got angry and kicked the locker, and it finally opened!

I am very proud of my sister. She is not only talented but also very hardworking. I love her very much and I am glad to have her as my sister.

希望这个示例能帮助你写出一篇关于姐姐的优秀英语作文!如果有更多具体的要求或想要添加的细节，请随时告诉我。