Guidelines for subject lines

Yesterday I mentioned that subject lines are NOT headlines in the classic sense.

My first subject line guideline reinforces that:

1. Less specific subject lines get higher opens.

Some classic subject lines that are hard to beat are very short and vague:


“quick question”

“This is ridiculous”

These look like personal messages—it’s almost impossible not to open them to be sure.

When would you want to use an approach like this?

There are times where you just want to maximize opens. One example might be the final “ends soon” email of a limited-time offer.

Or when you’re trying to “reactivate” a subscriber who has stopped opening emails.

Or if you’re doing an email outreach campaign to people who don’t know you yet.

These are pretty specific situations though.

Generally you want to…

2. Start with the direct approach first.

When you’re introducing something new to a list of people who already know you, use a clear, direct subject line.

Call out a major benefit that singles out your best customer.

Hint at any kind of special offer:

“Best deal EVER on PluralSight?”

“Save $50 on my ‘learn programming languages quickly’ system”

I’ve found that it doesn’t pay to be “cute” or try to back your way into announcing a new product or special deal.

Using a more specific subject line will usually result in lower open rates—but more of the right people will end up reading.

3. Include “power words” if relevant.

Including “download” in the subject line works well.

“Video” is another good one.

4. Use the word “you” in the subject line.

One technique I use a lot is a subject line that at first glance appears to refer directly to the recipient.

This is particularly effective if the subject line has an alarming or accusatory tone.

One of my highest open rate emails recently had the subject line:

“You money-grubbing SOB”

Others that have worked really well:

“You’re fired”

“You’re a fraud”

“Why are you spamming me?!?”

Use this approach at your own risk. These work because they cause a momentary jolt of panic in the recipient.

People then either get mad, or if the email is really good, they’ll feel relieved that they still have a job and actually enjoy the content more.

Best used sparingly, and with caution.

5. Play with formatting that stands out.

The majority of subject lines that people see follow a predictable set of rules.

They contain several words, correctly spelled.

The words are separated by spaces.

They appear as simple bolded black text.

They are “left-aligned” in the inbox.

Breaking with any of these conventions can make your subject line more noticeable.

Emojis can add color.

Numbers or special characters tend to stand out from regular letters.

Repeating words or letters can produce a different look:


Shorter subject lines create a different look than your standard 30-character subject line. So do SUPER long ones.

The thing to keep in mind with all of this:

Have fun, tinker around, and don’t sweat the individual open rates that much.

You’ll get more readers by sending 3 emails with OK subject lines than by sending 1 with a perfect subject line.