Cutting through the noise in someone’s inbox is hard enough, but writing a subject line that actually gets a B2B buyer to open your email? That’s a headache, even for seasoned sales pros. If you’re sending cold emails and tired of guessing what’ll work, this guide’s for you. We’ll walk through using Lavender—a tool built to help sales teams write better emails—to sharpen up your subject lines, avoid common traps, and (hopefully) get more responses from real decision-makers.
Let’s get practical.
Why Subject Lines Matter (and Why Most Advice Sucks)
Every sales email lives or dies by the subject line. If it’s boring, generic, or screams “sales pitch,” your message is doomed before it’s even read. The problem: most advice online is either recycled fluff (“just be personal!”) or borderline spammy (“use RE: for everything!”).
Here’s what actually matters: - Clarity beats cleverness. Subject lines aren’t a spot for poetry or clickbait. - Relevance wins. If it’s about the recipient, not you, you’re on the right track. - Testing matters way more than tips. What works for one list won’t work for another.
That’s where a tool like Lavender can actually help—by giving real-time, data-backed feedback, instead of generic “best practices.”
Step 1: Get Set Up with Lavender
Lavender is a browser extension and web tool that plugs into your email (Gmail, Outlook, etc.). If you’re reading this, you probably already have access, but if not:
- Install Lavender from their site and connect it to your email platform.
- Set up your profile—tell it about your role and industry for more tailored feedback.
- Open up your email composer so you can work with Lavender side-by-side.
No need to overthink the setup. You’ll get more out of Lavender the more you use it, so don’t worry about making it perfect on day one.
Step 2: Write a Baseline Subject Line (Don’t Overthink It)
Before you start optimizing, jot down a subject line you’d actually send. Something you’d type if nobody was watching—no fancy tricks, no pressure.
A few starting points: - Refer to recent events (“Congrats on the funding round”) - Mention a mutual connection (“Quick question from [Mutual Contact]”) - Call out pain points (“Idea for reducing onboarding headaches”)
Pro tip: Don’t try to “Lavender-ize” your subject line before you’ve even written it. The tool works better when you start with something raw.
Step 3: Use Lavender’s Subject Line Scoring
Here’s where Lavender can save you some guesswork. As you write, it’ll show a subject line score—usually a number out of 100—and highlight what’s working (and what’s not).
What Lavender looks for: - Length: Shorter is usually better. Under 7 words is a good rule of thumb. - Spam triggers: Words like “free,” “urgent,” or “reminder” can tank deliverability. - Personalization: Are you using their name, company, or something specific? - Clarity: Is it obvious what the email is about?
Don’t obsess over the score. The number is useful, but it’s not gospel. Sometimes a 72 out of 100 outperforms an 89 because it’s more relevant to your audience.
Step 4: Iterate—But Keep It Simple
Now’s the time to tweak. Here’s how to get the most from Lavender’s suggestions without losing your mind:
- Adjust for clarity. If your subject line is vague (“Quick question”), add context (“Quick question about onboarding”).
- Drop the fluff. If Lavender flags filler words, ditch them.
- Personalize, but don’t fake it. Using someone’s name works—if it’s natural. Don’t just mail-merge first names and call it “personalized.”
- Avoid spammy phrases. If Lavender flags terms like “act now” or “limited time,” trust it. Even if you see those working in marketing emails, they’re poison in B2B cold outreach.
Keep making small changes and watch how the score and feedback shift. Don’t get hung up on chasing a perfect score—focus on what feels direct, relevant, and human.
Step 5: Test in the Real World
A high Lavender score is nice, but it means nothing if nobody opens your emails. Here’s how to run a simple, honest test:
- A/B test subject lines on real prospects. If you send 100 emails, split them 50/50 with two different subject lines.
- Track open rates over a few days. Don’t obsess over tiny differences; look for clear winners.
- Ignore vanity metrics. A high open rate doesn’t matter if nobody replies. Track replies, too.
If something weird is working (a subject line you thought was “meh” gets more opens), trust the data and use it. If all your subject lines underperform, try going shorter, clearer, and more specific.
What Works, What Doesn’t, and What to Ignore
What actually works (most of the time): - Specificity: “Idea for [company]’s onboarding” beats “Quick question.” - Brevity: Busy people don’t read long subject lines. - Honest personalization: Referencing a trigger event (“Saw you hired a new CTO”) works better than lazy mail merge.
What doesn’t: - Tricks and gimmicks: “RE:” or “FWD:” when it’s not a reply gets you flagged. - Vague flattery: “Loved your recent article” (when you clearly didn’t read it) is transparent. - Clickbait: “Important message for you” just screams spam.
What to ignore: - One-size-fits-all “winning” templates. What works for a SaaS company in San Francisco won’t necessarily work for a manufacturing company in Ohio. - Over-optimization. Chasing a 100/100 score at the expense of sounding human is a waste of time.
Pro Tips for Getting the Most from Lavender
- Use it as a second set of eyes, not the final judge. Lavender is smart, but it’s not perfect. Trust your own judgment, especially if you know your audience well.
- Update your approach monthly. What works changes over time. Don’t be afraid to switch things up.
- Pair with real feedback. Run your subject lines by a colleague or even someone outside sales. If they’d open it, you’re on the right track.
Keep It Simple and Keep Testing
At the end of the day, there’s no magic subject line that’ll get every B2B buyer to open your email. But using Lavender can take a lot of the guesswork—and the anxiety—out of writing subject lines that don’t suck.
Stick to clear, relevant, and honest. Test, tweak, and don’t overthink it. You’ll get better (and so will your results) the more you keep it simple and keep iterating.