In almost every e-mail application fifty characters is all the space you have to work with in the subject line to catch your readers’ attention and entice them to open your message. You might ask yourself how something so small can make or break your campaign’s success? Because most recipients use the subject line as the number one factor in deciding if they open or delete an e-mail.

Although only fifty characters, subject lines can be one of the most challenging components of your e-Newsletter or e-mail message. A good one can get your message opened, while a badly written one could spell oblivion in the trash, or even worse, their junk mail folder.

Because so much is riding on your subject line, I have come up with eight rules for crafting a good one. Be sure to review them before you send your next campaign.

Rule #1: Learn from Newspapers

If you want to write better subject lines, look to your local paper. The headline usually highlights a story’s most important fact in a very limited space. A subject line, in turn, should do the same thing, clearly state what your readers can expect if they open your message.

Rule #2: Test, Test, Test

I say this in almost every article I write on e-mail marketing. But test continually to determine what works.

Rule #3: Use the “From” Line to Support the Subject Line

The “from” line informs the subscriber who sent the e-mail, and the subject line sells the recipient on what you are trying to convey. If your “from” line lists your company name, you don’t have to repeat it in the subject line. But do consider branding your subject line with the name of the e-Newsletter so that it will stand out in recipients’ overflowing in-boxes.

Rule #4: List the Most Important Info First

Some e-mail applications allow more characters in a subject line than others, but most give you at least 50, including spaces. So, include the most important information in that first 50 characters. Also, make sure the cut-off doesn’t occur in a crucial word.

Rule #5: Personalize

Personalize subject lines based on users’ name or content preferences to increase open rates.

Rule #6: Watch Those Spam Filters

There’s a fine line between “catchy” and “spammy” when writing a subject line. Two things that most often trigger a spam filter include subject lines in all capital letters, and using more exclamation points than necessary. (Both look unprofessional.) In fact, we recommend against using exclamation points at all if you can avoid it.

Rule #7: Don’t Mislead

Don’t stretch the truth in the subject line or promise more than you can deliver, or make grand claims that they could view as a bulk, Spam message. Readers will think you dishonest (and reach for the report spam button) if your subject line doesn’t reflect the actual e-mail content.

Rule #8: Write and Test Early and Often

Writing the subject line is often the last and most hurried step, almost an afterthought. It should be the other way around. As you plan the e-mail campaign, start thinking about what will go into the subject line. That will help you sharpen your e-Newsletter or e-mail content.

Conclusion: Much to Learn, Much at Stake

This may seem like a lot of info to consider for 50 little characters in a subject line. But they are vital to your e-mail marketing success. It pays to get them right.