Email marketing can help your business grow, but a misstep can cause you to lose customers for life. Avoid the pitfalls with these dos and don'ts.

Do: Create a snappy subject line that doesn't sound like an ad. People are more likely to open email that has a simple, newsy, and direct header.

Do: Use HTML rather than plain text. A well-designed newsletter or pitch containing product photos will help you get your message across.

Do: Rely on list-management software or services to deal with subscription changes, bounces, and new opt-in subscribers who have clicked links on your site or in your email messages.

Do: Track your messages' effectiveness. Most list-management tools track open rates, numbers of subscribers who unsubscribe, and click-through response for representative rates from one service). Test different messages and subject lines to see which ones produce the best results.

Don't: Get blacklisted. Use a spam checker to see whether your email will pass through common filters or put you on a spam blacklist. Many mailing services have checkers of this type, and Lyris.com and Sitesell.com make similar tools available for free.

Don't: Use JavaScript or background images. These will not show up for recipients who are using Outlook 2007.

Don't: Fail to include an unsubscribe link and a physical mailing address with your message, as required by federal antispam law. Consider including a link to your company's privacy policy, too.

Don't: Assume that message recipients will see included images--some email programs won't display them. Provide text descriptions for all graphics, and make sure your message is clear without the images. Never send attachments.

Don't: Send at the wrong time. The best days for business-to-business mailings are Tuesday through Thursday before 3 p.m. For residential customers, evenings and weekends work best.