Email marketing that doesn't end up in spam - complete guide

Email has been the most profitable marketing channel for two decades, with an average ROI of 36 EUR for every 1 EUR spent (Litmus, 2024). But only if it reaches the inbox, gets opened and read. In this guide we walk the whole path: from choosing a platform, through the technical setup that keeps you out of the spam folder, to automations that sell while you sleep. Email is a mandatory part of our internet marketing service, but with the right tools you can set up a big part of it yourself.

Choosing a platform

The first step is the tool. The most popular platforms for 2026, by business type and size:

• Mailchimp - small business, up to 500 contacts free, easiest to start with, but gets expensive quickly as your list grows
• Brevo (ex Sendinblue) - EU-based, GDPR-friendly, charges by emails sent instead of list size, which is often cheaper for smaller businesses
• Klaviyo - the e-commerce standard, best automations, deep Shopify/WooCommerce integration, but also the priciest
• ActiveCampaign - B2B, complex automations, lead scoring
• HubSpot - full marketing stack (CRM + email + automation), makes sense only when you need everything at once

For most small businesses in Serbia we recommend Brevo - servers are in the EU (GDPR), the free plan covers up to 300 emails per day, and paid plans start at around twenty euros per month. Pick Klaviyo only once you run an online store with serious volume - that's where its price pays for itself through automations.

Advice from practice: don't choose a platform by feature count, but by what you'll actually use in the first year. Migrating your list later isn't complicated - but bad habits, like a purchased list or sending without segmentation, follow you wherever you go.

Deliverability - how to reach the inbox

Your email can be perfectly written, but if it ends up in the spam folder, no one reads it. Deliverability is the technical side of the story and it's where the whole game is won or lost - so let's start with the three acronyms that scare people the most.

SPF, DKIM and DMARC - explained in plain language

• SPF is a list of servers allowed to send email on behalf of your domain - like a guest list at a club entrance. If Brevo or Mailchimp aren't on the list, Gmail treats them as intruders.
• DKIM is a digital signature on every message - a seal proving the email really comes from your domain and no one tampered with it in transit.
• DMARC is the rule telling the receiver what to do when SPF or DKIM fail (reject, send to spam or let through) - and it sends you reports on who is trying to send email in your name.

Good news: you don't need to understand the technology behind it. Every platform gives you ready-made records in its settings that you simply copy into the DNS at your registrar or hosting provider. A 15-minute job, done once. Since 2024 Gmail and Yahoo require all three records from anyone sending larger volumes, plus one-click unsubscribe - this is no longer optional.

The rest of the hygiene rules

1. A separate sending subdomain - e.g. mail.yourbusiness.com instead of the main domain, so complaints can't endanger your business email
2. A clean contact list - no purchased lists and no addresses that haven't opened anything in over 12 months
3. Double opt-in - the user confirms the signup with a click in the email, so your list contains only people who actually want you
4. A visible, one-click unsubscribe link - whoever can't easily unsubscribe clicks 'Report spam', which is much worse
5. Gradual warm-up - don't blast thousands of addresses from a new domain right away, start with the most active part of your list and expand

Test: send the campaign to yourself on a Gmail, Outlook and Yahoo address. Inbox - great. Promotions tab - not terrible, it still gets read. Spam - you have a problem, start with the DNS records. Tools like mail-tester.com and Google Postmaster Tools show you exactly where it's failing.

Subject lines that get opened

The subject line is the first and often the only filter - based on it, the recipient decides in a second whether to open the email at all. What works in practice:

• Length: 30-50 characters (longer gets cut off on mobile, where most emails are opened)
• Personalization: use the name - 'John, this is for you' visibly lifts the open rate in practice
• Create curiosity, don't say it all - 'What 90% of businesses get wrong with newsletters' beats 'Newsletter tutorial'
• Avoid spam trigger words - FREE!!!, 100% GUARANTEE, BUY NOW
• Emoji optional - small doses and only when relevant (📈 with a quarterly report, not ❤️ on everything)

Don't forget the preview text either - the line shown right below the subject. Instead of the default 'If you can't see this email...' use it as a second chance to earn the click.

A/B tests are your friend - every platform lets you send two subject line versions to a smaller part of the list, see which opens better, then send the winner to the rest.

List segmentation

Sending the same email to your entire list is the biggest mistake in email marketing. Open rate drops, inactive contacts pile up, and over time Gmail and Outlook start treating you as a spammer - which hurts delivery even to the people who want your emails.

Basic segmentation of every email program:

• Active vs inactive (did they open any email in the last 90 days?)
• Customers vs prospects (have they already bought something?)
• By interest category (e.g. the product category they browse or buy)
• By location (local offers and events)
• By value (VIP customers, mid, new)

Example from practice: a pet supply store that separates dog owners from cat owners and sends each group its own offer typically outperforms the same offer sent to the whole list. Relevance is the only real shortcut to the click.

Rule: it's better to send a relevant email to 30% of the list than a generic one to 100%. The rest of the list waits for a campaign that's meant for them.

Automated sequences

The biggest win in email marketing: automations are set up once and work while you sleep. Six sequences you should have:

1. Welcome sequence - 3-5 emails for new subscribers, introduces the brand and first offers
2. Abandoned cart - brings back customers who left a full cart (e-commerce only)
3. Post-purchase - thanks, instructions on how to use the product, cross-sell
4. Win-back - reactivates inactive subscribers (90+ days without opening)
5. Birthday/anniversary - personalized offer for a birthday or signup anniversary
6. Browse abandonment - if someone viewed a product several times without buying, remind them

What a good welcome sequence looks like

1. Email 1, immediately after signup: welcome plus whatever you promised - discount, guide, checklist
2. Email 2, after 2 days: the brand story - who you are, why you exist, what makes you different
3. Email 3, after 4-5 days: social proof - customer reviews, bestsellers, case studies
4. Email 4, after 7 days: a concrete offer with a deadline

Similar timing logic applies to abandoned cart: the first reminder within a few hours while the intent is fresh, the second after 24 hours, the third after 2-3 days - possibly with a small discount, but not every time, so you don't teach customers that an abandoned cart means a discount.

Klaviyo benchmark: well-set automations account for 30-40% of email revenue in e-commerce, while campaigns (manual, planned sends) bring the rest. You don't have to do everything at once - start with the welcome sequence and abandoned cart, then add the others once the first two are running.

Measuring results

Key metrics and rough industry averages:

• Open rate - 20-30% average (higher means a better subject and a more relevant list)
• Click rate - 2-5% (is the content and link in the email actually relevant?)
• Conversion rate - 1-3% (sale or lead after the click)
• Unsubscribe rate - below 0.5% (higher means you send too often or irrelevant content)
• Bounce rate - below 2% (higher means invalid addresses in your list)

Opens and clicks are half the story - especially since Apple Mail Privacy Protection started artificially inflating open rates. You see the real result only when you tag the links in your emails with UTM parameters and track conversions in GA4. We explained the step-by-step setup in our marketing tracking guide with GA4 and Pixel.

The metric that matters most in the end: revenue per email sent. The goal is for every email to bring more revenue than sending costs - and sending costs almost nothing.

Frequently asked questions

How often should I send a newsletter?

As often as you have something worth saying - for most small businesses that's 2-4 times a month. Worse than sending rarely is chaos: a list that hears nothing for months and then suddenly gets five emails in a week. Consistency beats frequency.

Can I email people who never signed up?

No. Purchased lists and 'scraped' addresses are legally risky (GDPR applies the moment you have a single EU contact) and practically useless - such contacts don't open, they report spam and wreck your domain's reputation. You build the list with a lead magnet: a discount on the first purchase, a useful guide or a checklist in exchange for the signup.

How much does email marketing cost?

To start - almost nothing. Brevo and Mailchimp have free plans that are plenty for your first few hundred contacts. More serious plans for smaller lists run from 20 to 50 EUR per month. That still makes email the cheapest channel that directly sells.

Conclusion

Email marketing isn't dead - only bad email marketing is. The order of moves is clear: fix deliverability (SPF, DKIM, DMARC and a clean list), pick a platform you'll actually use, grow the list through double opt-in, segment instead of blasting the whole base, and let automations sell while you sleep. Measure results in revenue, not open rate.

If you'd like someone to set all of this up for you end to end - from DNS records to the welcome sequence - check out our internet marketing package or send an inquiry through the contact form. We work with Klaviyo, Mailchimp, ActiveCampaign and Brevo.