Here's one of those sounds obvious, bears repeating kind of things:

When you create an away auto-reply for your email, don't forget to:

  1. Spell check and proof it (yes, both!)
  2. Double check days and dates
  3. Send it to yourself first to check formatting

The first two are obvious, but the last one is equally important. In the last couple of days I've gotten two auto-replies from people that didn't reflect well on the senders. One had incorrect dates (2009, anyone?) and the sender's own name misspelled. The second had unfortunate formatting errors that made it not only look sloppy but hard to read.

With email being one of, if not the, primary ways we communicate, taking care in preparing something as mundane as an out-of-office reply carries more importance.