Getting your cold emails into the inbox is harder than ever. Spam filters keep getting smarter, and even legit emails can wind up in the Promotions tab or, worse, spam. If you’re using Warmupinbox to warm up your domain and improve deliverability, you’re off to a good start. But it’s not magic. Optimizing your actual email templates is still the make-or-break factor.
This guide is for anyone who’s tired of guessing why their emails aren’t landing in the inbox. Whether you’re running cold outreach, newsletters, or just want your emails to stop disappearing, here’s how to get the most out of Warmupinbox—and your templates.
Step 1: Start With a Clean, Realistic Template
Spam filters are ruthless about cookie-cutter templates. If you’re using the same tired copy as everyone else, you’re asking to get flagged. Here’s how to build a template that gets you past the first hurdle:
- Write like a human: Ditch the salesy language and buzzwords. “Revolutionary solution” and “limited-time offer” scream spam.
- Personalize, even in tests: Even if it’s a test template, add fields like
{{first_name}}or specific company details. - Keep it short: Think of your own inbox. Would you read a wall of text from a stranger?
What to ignore: Overly clever subject lines or clickbait. They might get opened once, but they’re a red flag for filters.
Pro tip: Paste your template into a plain text editor before uploading to Warmupinbox. This strips weird formatting that can trip up spam filters.
Step 2: Avoid Spam Trigger Words and Formatting
There’s no definitive list of “bad words,” but certain phrases and formats consistently set off alarms. Here’s what to watch out for:
- Subject lines: Avoid ALL CAPS, too many exclamation marks, and phrases like “Act now,” “Free,” or “Guaranteed.”
- Body copy: Steer clear of “100% satisfied,” “Click here,” “Best price,” and similar language.
- Formatting: Don’t go heavy on bold, colored text, or huge fonts. Stick to standard fonts, normal sizes, and minimal styling.
- Links: Limit to one or, at most, two links. Make sure the hyperlink text matches the destination URL (no bait-and-switch).
What works: Keeping things plain. A simple, conversational email is your best bet.
What doesn’t: Copying templates from “email swipe file” PDFs. They’re overused and often outdated.
Step 3: Use Proper Authentication and Domain Setup
Warmupinbox can help warm your domain, but if your authentication is off, nothing else matters. Spam filters check this first.
- SPF, DKIM, and DMARC: Set these up correctly. Double-check using online tools (like MXToolbox). If you skip these, you’re wasting your time.
- Sending domain: Use your own domain, not a free Gmail or Yahoo address.
- From name and address: Use a real person’s name, not “info@” or “no-reply@.”
Pro tip: If you’ve just set up a new domain, give it a few weeks in Warmupinbox before sending real campaigns. Rushing this step almost always backfires.
Step 4: Tweak for Engagement Signals
Filters don’t just look at what you write—they look at how people interact with your emails.
- Ask a question: Give recipients a reason to reply. Replies are the #1 positive engagement signal.
- Encourage whitelisting: A quick “Please add me to your contacts” in your email footer can help.
- Don’t send attachments: Especially not on first contact. Attachments are a classic spam flag.
What works: Two-way conversation. If you get even a handful of genuine replies, your deliverability goes up.
What doesn’t: Sending out mass, one-way blasts. If nobody replies, filters figure you’re just spamming.
Step 5: Rotate and Refresh Templates Regularly
Even the best template will get stale over time. Spam filters adapt, and if you’re sending the same thing over and over, you’ll get caught.
- Create template variations: Change up your subject line, intro, and closing paragraph every few weeks.
- A/B test in Warmupinbox: See which versions end up in spam vs. inbox. Don’t just guess—use the data.
- Retire templates that start to struggle: If a template suddenly gets more spam placements, stop using it.
What to ignore: The idea that you need dozens of templates to “beat the system.” Quality beats quantity.
Step 6: Monitor Results—Then Adjust
Don’t just set it and forget it. Warmupinbox gives you detailed placement tracking, so pay attention.
- Check your inbox vs. spam rates weekly: Look for trends, not just one-off results.
- Adjust based on feedback: If you see a dip, tweak your template and rerun the warmup.
- Stay realistic: Even the best senders get a few emails in spam. Aim for improvement, not perfection.
Pro tip: If your deliverability tanks after a change, roll back and try something else. Don’t panic—just iterate.
Step 7: Don’t Overthink “Advanced” Tricks
There’s always someone pushing the latest hack: invisible text, image-only emails, or crazy personalization scripts. Most of these do more harm than good.
- HTML vs. plain text: Plain text nearly always lands better for cold outreach. If you must use HTML, keep it simple—no banners, no complex layouts.
- Tracking pixels: These can set off filters, especially if you’re sending to new contacts. Use sparingly, if at all.
- Emoji in subject lines: Fine for newsletters, risky for cold outreach.
What works: Sticking to the basics. Fancy tricks rarely beat a clean, honest template.
Step 8: Use Warmupinbox Features Wisely
Warmupinbox isn’t just a “set and forget” tool—it can help you spot issues before you send real campaigns.
- Run new templates through warmup: Don’t just warm your domain. Add your actual cold email templates to a Warmupinbox sequence and watch the results.
- Check placement reports: See if certain templates consistently land in spam or Promotions. Adjust before you launch a full campaign.
- Use inbox rotation: If you’re sending from multiple addresses, rotate templates so you’re not blasting the same message from every inbox.
What to ignore: The promise that “warmup” alone is enough. It’s helpful, but not a silver bullet.
Keep It Simple and Iterate
You don’t need to reinvent the wheel or chase every new deliverability hack. The basics—clean templates, real authentication, and steady monitoring—will beat complicated setups every time. Keep your emails human, watch your results, and don’t be afraid to tweak as you go.
If you’re using Warmupinbox right, it’s a great safety net—but the real difference comes from the emails you actually send. Focus there, and the inbox is a lot closer than you think.