When Diane Darling's frustrated email exchange with a coworker in Australia was passed on to a boss, she found herself in the CEO's office.'He handed me a copy of my e-mail and said, 'I just want to know your thoughts on this,'' recalls Ms. Darling, who had criticized her manager. 'It's something you hope happens in your 20s. Heaven help you if you do that later in your career!'Like Darling, who wasn't fired but left the company shortly afterward, many employees have learned the dos and don'ts of e-mail the hard way. Some workers get tripped up by e-mail etiquette. Others fall into a black hole of inefficiency because of ineffective electronic communication habits.The importance of good e-mail skillsWith the volume of e-mail growing rapidly, good e-mail skills have become more important than ever, some workplace experts say. For example, 1 in 10 employees spends more than four hours a day handling electronic tasks; nearly half spend at least two hours, according to a survey of 840 companies conducted this year by the American Management Association and the Policy Institute.Junk e-mail contributes to the problem. But another more deeply rooted issue is ineffective communication practices. Employees' poor writing skills cost American corporations $3.1 billion annually in training costs, the National Commission on Writing estimated in a September report.That's why companies—and individuals—are beginning to coach workers on how to use the medium effectively.With more than 800 e-mails pouring into her inbox daily, Sharon Clay would be overwhelmed if she didn't focus on efficient e-mail techniques with laser-like intensity.'People should go through their e-mail in the morning like calisthenics(健身操)', says Ms. Clay, an architectural manager at Nvidia Corp. While she offers one-on-one e-mail coaching, her company, which makes graphics and digital-media chips for computers, has begun holding e-mail training classes for employees.Clay suggests that workers go through their in-boxes methodically and thoroughly every morning, and more often if necessary. Being predictable in one's response time is an essential part of being a good communicator, she adds.Here are strategies Clay and others employ to handle the electronic flood:Don't forget the phoneIf your e-mail has more than three points or questions, you're probably better off calling or meeting someone when you can have a discussion based on his or her answers.Create an alert systemUse color-coding, fonts, and styles to prioritize your inbox. These visual hints enable you to recognize and respond to critical emails quickly. Lower-priority items can be moved into folders to be dealt with later. Clay combs through most of these folders at least once a week.Remember your grammarIt's not just a courtesy. It ensures clear communication—and may determine your business success. Half of all companies surveyed by the National Commission on Writing took an employee's writing skills into account when making promotion decisions. So while it may save you time to leave out nouns and use abbreviations, don't do it. It can confuse co workers. Also, use clear and concise subject lines.Watch whom you copy on e-mailsMake sure your recipients have the necessary context to u