This requires rules. If your e-mail system has integrated group scheduling, use the calendar function to receive meeting notices that are automatically placed in your calendar. For employees such as sales managers, who naturally receive very high volumes of e-mail, create a library of boilerplate texts that assistants or secretaries might also use to reply to commonly received requests. Develop the habit of handling messages only once. Then delete or file them.
Common sense can help in creating less e-mail.