spent months deep-diving into cold email infrastructure. Not just sequences or tools-domains, DNS, SPF, DKIM, DMARC, warmup, bounce rates, all the boring stuff that actually gets mail into an inbox. made plenty of mistakes. Here's what I'd tell my past self.

1. Your copy isn't the first problem
Everyone obsesses over subject lines. But the best email in the world lands in spam if your setup is trash. Before rewriting for the 20th time, check SPF, DKIM, DMARC, sending volume per mailbox, lead verification, and bounce rates. Most "cold email isn't working" is infrastructure, not copy.

2. Never use your main domain
Obvious once you know it. I've seen businesses blast hundreds from their primary domain. Why risk your company's email reputation for outbound? use separate secondary domains-professional ones, not $2 garbage.

3. More mailboxes ≠ more leads
Everyone wants to scale volume. 10 mailboxes, 50, 100. but nobody asks: do i actually have 10,000 relevant people to contact? Sending 500 targeted emails beats blasting 10,000 random scraped contacts. infrastructure lets you scale, but it doesn't fix a bad list.

4. Lead gen and cold email are two different problems
Lead gen is finding the right people. Cold email is reaching them. perfect infrastructure gets zero clients if your targeting is vague. "Founders in the US" isn't targeting. "B2B SaaS founders with 5-30 employees who just launched and are hiring backend engineers" is closer. the more specific, the easier the email.

5. Personalization doesn't mean AI-generated fluff
"Hey John, I noticed your incredible journey from Engineer to Founder.." Nobody talks like that. Useful personalization is simple: why this company, what problem do they have, why now? that's enough.

6. stop explaining your whole product in the first email
As a dev, i wanted to explain architecture, features, integrations. nobody asked. The goal isn't to close-it's to get a reply. My emails now answer: why me, why are you contacting me, is replying worth my time?

7. Reply handling is underrated
Everyone focuses on sending. but what happens when someone replies? are replies going into unmonitored inboxes? Can you see which campaign generated the conversation? can multiple people manage replies? Sending is easy, managing conversations is where the business starts.

8. don't automate what you don't understand manually
I'm a dev-my instinct is to build. But automating a process you don't understand yet wastes time. do lead gen manually first. Send small campaigns. Read replies. Understand why people say no. Then automate the repetitive parts. the software you build after understanding the workflow is completely different.

9. Cold email isn't magic
You still need a good offer, proof, and understanding of the customer's problem. cold email is just distribution. It can put your offer in front of the right person, but it can't make a bad offer good. Technical setup, lead quality, copy-they all have to work together.

Still learning every week. Curious what mistakes others made starting out.