Forget everything your fourth-grade teacher told you about flowing capitals and indented addresses. Here is how the Post Office would like to see your cards addressed:
MR AND MRS STEPHEN EWER
P O BOX 1234
ANYTOWN WA 98765-4321
The rules are:
(1) use block capital letters,
(2) do not use periods or commas,
(3) use proper postal abbreviations and (4) use the nine-digit zip code, if you know it.
Missing Zip codes? The Internet makes it easy. Find the USPS Zip Code Locator at http://zip4.usps.com/zip4/welcome.jsp .
Get a list of state and addressing abbreviations at http://www.usps.com/ncsc/lookups/usps_abbreviations.htm.
Today's software can often go a step further and add a postal bar code to the envelope or label, but CEO hesitates to raise the ire of the Purists to quite that extent. Let's just say if you're on the Geek Cool side of the fence, it's a nifty touch, and the Postmaster will thank you.