First impressions are key. Would you show up to a black tie event in your favorite Netflix binge-watching sweats? Of course not. Your sales email subject lines are the first impressions you project to your prospects with every email you send. Are you putting on your best suit every time you hit send?

We've learned a lot about what works by analyzing the data from tens of thousands of our own emails. Our catchy email subject lines for sales have five key traits in common.

We think number 1 & 4 are great for recruiting emails :-)

4 Tips for Top-Performing Email Subject Lines

1. They're short, sweet, and straight to the point.

2. They're written in a human way - non-formatted, casual subject lines seem more personal.

3. They're personal - they directly reference the company or the prospect's name.

4. They include a simple call to action.

5. They're relevant to the role, title, and persona of who we are reaching out to.

If that advice is not enough to set your sales or recruiting team in motion, here are the actual top performing email subject lines our team has used.

Top 4 Sales Email Subject Lines

#1: The Quick Call (Personalized)

What to say:

"Quick call HireResources - Your name"

Results: 75% open rate

Why it works: The Quick Call Subject Line is the subject line equivalent of a SMART Goal (optimized sales reps everywhere are like: "Yaaas SMART Goals!"). For those who don't know, S.M.A.R.T. stands for Specific, Measurable, Attainable, Relevant, and Time-Bound. This email subject line is:

Specific: Your prospect knows who you are, who you're trying to reach (their company name), and what you want (a quick call).

Measurable: You measure the open rate. Moving on.

Attainable: A "quick call" is a very low-barrier-to-entry activity for your prospect, something that won't take more than 10 minutes precious time away from their day and requires no preparation (on their part).

Relevant: Make sure you include their company name (and check it twice!). #personalization

Time-Bound: The "{{weekdays_from_now 2}}" field will automatically populate with a day in the very near future, like Wednesday or Thursday (ooh, fancy). By including a deadline, you give your prospect a sense of urgency.

#2: The Follow Up

What to say:

"Wanted to make sure you got my email"

Results: 66% open rate

Why it works: There are few sales tactics that beat the effectiveness of a quality email follow up. Your prospects are busy, and your first cold email can get lost in The Inbox Ocean, so this subject line is just the thing to remind your prospect that "Oh $#@! I need to respond to that email."

#3: The Virtual Handshake

What to say:

"{{sender.first_name}} from HireResources"

Results: 58% open rate

Why it works: A strong handshake makes a great first impression, and this email subject line extends a bold and assertive virtual handshake to your prospect. It introduces your name and company, and leaves plenty of space for the (equally strong) first sentence of the email to show up in the web browser or mobile preview.

This subject sets the tone for a solid person-to-person relationship between you and your prospect.

#4: The Connect Request

What to say:

“Connect?”

Results: 52% open rate

Why it works: It’s concise, purposeful, and matter of fact - the call to action is a simple and quick ‘yes’ or ‘no’ answer. But it's also ambiguous enough to create a sense of curiosity. We’re wired to be curious - so much so that the reward centers in our brain light up whenever our curiosity is piqued. This approach makes your recipient want to know more (Connect about what? And why?) and open your email.

The fact that this subject line is only eight characters long means that the first sentence in your email will probably show up in the preview on most mobile apps and email clients. This gives your messaging in that first sentence another chance to make a first impression.

The simple "Connect?" subject line raked in a whopping 71% open rate just last year, and it's still on the leaderboard.