假设我们要描写一位年轻男子的外貌，可以按照以下步骤来写英语作文：

Step 1: 确定描写对象

我们选择一位名叫Tom的年轻男子作为描写对象。

Step 2: 描述身材特征

首先，我们可以从身材特征入手，比如：

Tom is a tall and slim young man. He has a well-proportioned body with broad shoulders and narrow waist. His arms and legs are long and slender, giving him an elegant and agile look.

Step 3: 描述面部特征

接着，我们可以描写Tom的面部特征，比如：

Tom has a handsome face with sharp features. He has a high forehead, deep-set eyes, and a straight nose. His lips are thin but well-defined, and his jawline is strong and chiseled. His complexion is fair and smooth, with a healthy glow on his cheeks.

Step 4: 描述头发和眼睛

我们还可以描述Tom的头发和眼睛，比如：

Tom has thick, dark brown hair that falls in soft waves over his forehead. His eyes are a bright shade of blue, with long lashes that make them look even more striking. They are expressive and seem to reflect his inner thoughts and emotions.

Step 5: 描述穿着风格

最后，我们可以描写Tom的穿着风格，比如：

Tom likes to dress stylishly and confidently. He often wears tailored suits with crisp shirts and colorful ties. In his casual wear, he prefers jeans and t-shirts that fit him well and show off his toned physique. He also likes to wear accessories like watches and cufflinks to complete his look.

总结：

通过以上步骤，我们可以描写出一位年轻男子Tom的外貌特征，包括身材、面部、头发、眼睛以及穿着风格等方面。在写作时，可以注意运用形容词和形容词短语来丰富描写，同时也要注意使用恰当的词汇和语法结构。