Management
As management classes stress, writing is an essential skill. One attribute of an effective business manager or lawyer is the ability to write well. The more writing practice you have now, the more likely you are to be an effective writer in your professional career. It's worth recognizing that a relaxed and informal style of writing, such as most of us often use in email, may not be appropriate in a professional setting.

Know your purpose for writing, develop a strategy (such as ordering reasons from most to least important or from least to most controversial), avoid ambiguity, use active voice instead of passive, and choose a clear layout. These principles will help you whether you are drafting a contract under the statute of frauds or writing routine communications to a supervisor or client.

Source: Angelo Kinicki and Brian K. Williams, Management: A Practical Introduction (New York: McGraw-Hill/Irwin, 2006), p. 507.