Even great emails end up in spam if you skip the basics. Here are the 8 fixes that actually move the needle on inbox placement — based on what Gmail, Outlook and Yahoo evaluate.
Why this matters: One spam-trap hit or a 0.5% complaint rate can throttle your domain across providers for weeks. Prevention is faster than cleanup.
1. Authenticate every send
- Publish SPF, DKIM and DMARC on your sending domain.
- Move DMARC from
p=nonetop=quarantineonce alignment is clean. - Use a domain that matches your brand — never a free webmail address as the From.
2. Send only to opted-in contacts
- Use double opt-in for every signup form.
- Never buy lists — spam-trap addresses kill domain reputation in one campaign.
- Suppress hard bounces and inactive contacts older than 6 months.
3. Write content that doesn't trip filters
- Balanced text-to-image ratio (avoid all-image emails).
- No spammy phrases ("FREE!!!", "100% guaranteed", all-caps subject).
- Single, clean HTML — no broken tags or hidden text.
- Always include a plain-text alternative.
4. Warm up new IPs and domains
- Start with 200-500 of your most engaged contacts.
- Double the volume every 1-2 days.
- Watch open and complaint rates daily for the first 4 weeks.
5. Keep complaint rate under 0.1%
- Make the unsubscribe link obvious in every email.
- Honor opt-outs immediately.
- Add a one-click List-Unsubscribe header.
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