E-mail Management
Most software development teams spend their days switching back and forth between working on projects and writing or responding to e-mails. That's why it's important to encourage your team to use e-mail as efficiently as possible.
One simple way to greatly increase the efficiency of your team's e-mail communication is to have everyone agree on what sort of response time they expect when they flag a message as "high priority" versus one that is "low priority" or not flagged at all.
For instance, my team at TechSoup has agreed that marking a message as "high priority" means you'd like to get a response no later than the end of the day. A "low priority" flag indicates that a response isn't necessary. Messages without a priority should be answered within a week, though two days tends to be normal when it's not crunch time around the office.
Of course, team members can indicate a more specific "respond by" date in the body of their message if they'd like--in fact, they're encouraged to, so as to avoid misunderstandings.
Likewise, a message that needs a response as soon as possible rather than by the "end of day" might have URGENT in the subject line in addition to the "high priority" flag. (However, I like to remind team members that they shouldn't be afraid to pick up the phone and make a call if something is truly that urgent.)
Whatever your team decides, keep in mind that the goal of such an exercise is twofold: Not only will team members respond to important messages more promptly, but they'll also be able stop wasting valuable time responding to messages that can wait until later.