阿巴阿巴阿巴……你这是逐字从中文翻译的吧？建议直接用中文给我说一遍，我给你写……满分15分的话，我作文一般都是14、15分。
I am glad to hear of you will come to my home.
of 改成 that，或者去掉。
Welcoming to your coming!
写作 Welcome! 就可以了。
In addition, I have something will tell you.
will 改成 to，“我有一些事要告诉你”不应该这么直译[捂脸]。
First, we'll take part in activity of school.
“activity of school”看着有点不舒服，建议改成“an activity of our school”。
What's more, we will look over towntown to visit the beautiful sites in the afternoon.
towntown 什么鬼……你想说的是下午用浏览器看美丽的网站？建议写作 We will use a browser to visit the beautiful sites in the afternoon.
In the end, we could watch TV and play games or chat with each other.
从语境看，这句话是将来时态，could 换成 can。
“watch TV and play games or chat with each other” 建议改成 “watch TV, play games and chat with each other”。
I think you may will have a good experience.
两个情态动词也是够了……留下 will，去掉 may。
I am looking forward to your coming.
这个真没毛病。
虽然有的地方不确定错不错，但大部分很确定（比如may will，简直了）。
综合来看，10分左右吧……