首先，观点要鲜明，文章一定有一个明确的中心论点。
其次，层次要分明，一个中心论点通常有几个分论点支持,不同层次之间要分明，过度清晰自然。
再次，最后一段一般要总结全文,得出一个符合逻辑的结论，突出中心思想。
最后,文章一般采用一般现在时,语言要简洁有力，一般不采用口语。
请看下面例文：
Buying Lottery for Luck
Nowadays，many people are enthusiastic about buying all kinds of lottery tickets. The purpose of them is to realize their dreams of becoming rich. However, some people don't agree on this activity. They think trying luck on lottery is harmful. They believe that such practice is likely to make people expect good luck rather than hard work to achieve their goals.

I believe that it is a meaningful thing. It does more good than harm to our society. First, the money collected can be used to help the poor and the needed. Second, the accumulated money will be helpful to promote our welfare and make contributions to the whole society.

Moreover, if you are lucky enough, you may be rewarded. So I favor lottery tickets. If I have some spare money, Fll buy them.
请看下面一篇关于沙尘暴的例文：
Sandstorms
Sandstorms are getting more and more serious in some regions in the northern parts of China, especially, in spring. As the suffusing dust blocks out the sky, covering cities in dust, the storms bring much inconvenience and trouble to people’s daily life and work, and even claim some lives in some serious regions. Thus, it arouses the concern of the whole nation.
Naturally, there are many factors that cause this abnormal climate. To begin with, the encroachment of the desert in Inner Mongolia should take the main blame for the storms.
Besides, the continuous high temperature and little rain should also be heavily responsible for the high frequency of storms.
However，we shouldn’t only blame nature for the sandstorms because, to some extent, human beings should bear partial responsibility for this phenomenon. There’s no denying that it’s our destruction of vegetation and protective forests that makes the north-wind kick up the loose soil so easily, and thus form the storms. However, as a coin has two sides, the storms well sound the ecological alarm and should be regarded as sand penalty to man. In a word, the haunt of the storms repeatedly warns us that it’s high time we made laws to protect our ecological environment, restored the vegetation and planted more protective forests and took whatever effective measures to stop the rampant storms and restore our ecological environment.