Cold Email for Agencies: How to Close Retainer Clients in 30 Days
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Cold Email for Agencies: How to Close Retainer Clients in 30 Days

See how digital marketing agencies build cold email systems from scratch and close monthly retainer clients within their first 30 days.

ABT
Automated BDR Team
December 07, 2025
6 min read

The Starting Point

Grove Digital is a six-person marketing agency based in Austin, Texas, specializing in paid media and SEO for e-commerce brands. Their growth had relied entirely on referrals. When referrals slowed in Q3 2024, they had no outbound engine to fall back on.

They came to us with a clear goal: generate five qualified discovery calls per month from cold outreach. Budget: $1,500/month for tools and infrastructure.

The Setup

Target ICP: Direct-to-consumer e-commerce brands doing $2M–$20M in annual revenue, with active paid media spend but no dedicated agency relationship.

Toolstack:

  • Apollo.io for prospecting (filtered by revenue, headcount, tech stack showing Meta Ads and Google Ads pixels)
  • Instantly.ai for email sending
  • Two dedicated sending domains (not their primary domain)
  • Mailreach for warm-up

List building:** 300 accounts per month, 2 contacts per account (founder + head of marketing where available). Total: ~600 contacts per month.

The Email Sequence

They ran a 4-step sequence over 14 days:

  1. Day 1: Personalized opener referencing a specific product or ad creative they had seen from the prospect's brand, followed by a single question about their current paid media performance
  2. Day 4: Value-add email sharing a relevant case study from a similar brand
  3. Day 8: Short follow-up referencing the previous email, different angle
  4. Day 14: Break-up email with a low-friction CTA

Subject lines that worked:

  • "[Brand] — saw your Meta ads"
  • "quick question about your ROAS"
  • "idea for [Brand]"

Results (Month 1)

  • 600 contacts emailed
  • 47% open rate
  • 8.3% reply rate (50 replies)
  • 11 discovery calls booked
  • 3 new retainers signed (average value: $4,500/month)

Total new MRR from month one: $13,500 — a 9x return on their tool investment.

What Made the Difference

Hyper-specific targeting. Filtering for brands with active ad spend meant every prospect was a real potential buyer, not just a company that might theoretically need marketing services.

Personalization at the first line. Referencing a specific ad creative or product they had researched made the email feel far more human than typical agency outreach.

Low-friction CTA. They did not ask for a 30-minute call in the first email. They asked one relevant question. Replies led naturally to calls.

Month 2 Iteration

They added a LinkedIn touchpoint between email steps 2 and 3, sending a short voice note on LinkedIn to the same prospects. Call bookings increased by 40% the following month.

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