David Baker, vice president of e-mail marketing and analytical solutions at Agency.com, has some good advice about the second most important part of your email communications–the subject line. Read the whole article for a sound approach to planning and testing subject lines.

MediaPost EMail Insider Newsletter: Now Read This.

The biggest mistake I see in subject line testing today is testing solely on the offer itself (does $50 off pull better than $25 off? Does offering free shipping make a difference? — and so on). Remember the top hierarchy of an e-mail: 1. The subject line conveys the relevance of the communication 2. The opening statement in the e-mail supports the subject line and provides the main call to action/promotion/key message.