Yesterday I bought a book about how to inrich the composition.
What I need to do is memorize the sentences and phrases.
Sometimes I can not express what's in my mind precisely 
due to my lack of vocabulary.
I have to do something about it.
Cannot let the lack of vocabulary get in my way.

I read the book and get some reflections.
First, overcome the problems in usage.
Second, be both logical and combine with the topic tightly.
Third, 
get hang of the topic sentence, supporting ideas and concluding sentence.

The most crucial thing is practice makes perfect.
Work hard persisternly.  
I know I can do better than now.