How to Build a Lookalike Prospecting Engine in Clay (Step-by-Step for Startups)

Introduction

Most startups don’t have the time or budget to guess who might buy from them.

That’s why lookalike prospecting is such a cheat code. Instead of chasing random leads, you use data from your best customers to find others just like them. Essentially, you’re modeling your next 100 customers after the 10 who already said yes.

And with Clay, that process isn’t manual or messy. It takes what you already know about your ICP, layers on live data, and automatically finds qualified accounts that look and act like your existing customers. Then it sends everything straight to HubSpot so your sales team can actually spend time selling.

In this guide, you’ll learn how to turn customer data into a repeatable system for finding and converting more of the right people.

TL;DR: How do you turn your best customers into a prospecting engine?

• Start with a clean list of your best-fit customers.
• Enrich and qualify that list automatically with AI.
• Find new lookalike companies showing real buying intent.
• Track and manage everything directly in your CRM.

Step 1: How do you define your ICP Seed List in Clay?

The first step in building your lookalike engine is defining the audience you want to model from. Clay makes that simple with the Find Companies feature.

Inside Clay, open a new table and choose Find Companies. This is where you’ll build your seed list, the small group of companies that perfectly represent your ICP. Use the filters on the left-hand side to get as specific as possible:

• Industry: Select the industries that best describe your ideal customers. You can include multiple or exclude overlapping ones to narrow your focus.
• Company size: Choose ranges that align with your current customer base, whether that’s 10–50 employees or 500–1,000.
• Type and location: Filter by company type (private, venture-backed, nonprofit, etc.) and geographic region to match your market.

Once you’ve locked in your filters, exclude irrelevant sectors or outliers. This prevents your list from being cluttered with mismatched companies and keeps your data clean.

Then, add three to five of your best customers, the ones that best fit your ICP, into Clay’s Lookalike Generator. Clay will use those profiles to identify companies with similar firmographics and digital behavior patterns.

When you preview the results, you’ll see a live list of companies that match your ICP’s DNA, complete with details like name, description, size, location, and LinkedIn URL. Import that list into a new table, and you’ll have a solid, data-driven starting point for the rest of your prospecting workflow. From there, the most effective Clay users go deeper, building their ICP around pain, budget authority, and real buying intent, not just surface-level demographics.

Step 2: How do you clean and prepare that data?

Before you start enriching your list, you need to clean it. A cluttered table creates bad data that throws off every workflow that follows. 

Start by standardizing company names and domains. If your list mixes URLs, partial names, or inconsistent formats, Clay formulas can quickly fix that. Clean, uniform inputs ensure that every enrichment action hits the right record the first time.

Then, filter out what doesn’t belong. There’s no reason to enrich companies that you already work with or that don’t fit your ICP. Use logic columns to automatically remove:

• Existing customers or open deals already in HubSpot
• Companies outside your target region
• Accounts below your ideal size or headcount

Next, make sure those domains are still alive. Clay can check whether a site is active, redirected, or parked. That single step protects your credits and keeps your list focused on real, operating businesses.

Once you’ve done that, run a quick ICP check to confirm what’s left truly fits your audience. When every record is accurate, your enrichment becomes faster, cheaper, and far more reliable.

Clean data might not sound exciting, but it’s what makes every other automation work. When your list is solid, Clay and HubSpot can do what they do best: find, qualify, and convert the right people automatically. 

Real teams are already seeing the impact. IntroCRM cut its prospecting data budget by 65% using Clay’s creative workflows, proving that clean, structured data isn’t just more accurate, it’s more efficient.

Step 3: How do you enrich and qualify accounts efficiently?

Once your data is clean, move into automated lead enrichment to add the context that helps your team sell more effectively. This step gives every record depth by showing who’s behind the company, what they do, and whether they fit your ICP.

Start by adding people data. Clay can automatically pull titles, LinkedIn URLs, and tenure information. That way, you know exactly who you’re reaching out to and how long they’ve been in their role. It’s a simple way to identify decision-makers and avoid wasted effort.

Then layer in company data to understand the organization behind each contact. 

This includes:

• Estimated revenue or funding stage
• Department sizes and team structure
• Tech stack details, such as whether they already use HubSpot

Next, include funding and growth insights to prioritize who’s ready to buy. You can pull investor names, round types, and total funding raised. Companies that have recently secured new capital are often the ones expanding budgets or scaling teams.

To make enrichment efficient, use Clay’s “only run if” conditions so enrichment triggers only when a field is blank. That setup ensures you’re not wasting credits and only filling in what’s missing.

When data gaps remain, let Clay AI handle them. It can automatically write short company summaries that describe what the business does, which is ideal for adding as a note in HubSpot records.

Companies that combine multiple data signals, like job changes, funding rounds, and engagement patterns, see far higher conversion rates. Teams using Clay’s multi-signal enrichment turn 40-50% of prospects into meetings, compared to just 10-15% with traditional outreach.

The goal is not to collect every possible data point but to create a clean, qualified list your team can actually act on. Once you’ve enriched and qualified your accounts, you’ll have a high-confidence ICP list ready for lookalike prospecting. Startups that use AI to automate prospecting typically generate 30% more leads and build a 25% stronger qualified pipeline than teams relying on manual research.

Step 4: How do you identify companies showing buying intent?

Once you know who fits your ICP, the next step is to find out who’s ready to buy. Intent signals help you prioritize the companies that are actively investing in growth.

Start by identifying hiring activity and tech usage that signal buying momentum. 

In Clay, you can:

• Use the Find Jobs feature to uncover companies hiring for RevOps, Demand Generation, or Growth roles.
• Filter by company size, revenue range, and location to narrow your focus to those investing in your category.
• Add data points like website traffic, marketing team size, or open positions to gauge whether a company is scaling up.

When companies are hiring for roles that match your ICP, it’s often the clearest sign they’re about to spend.

You can also track which companies are using or researching tools like HubSpot. Combining that information with job data helps you pinpoint the ones that are both qualified and actively evaluating solutions like yours.

Clay-powered targeting identifies prospects showing at least three intent signals, such as hiring activity, tool research, and funding events, and boosts response rates by over 30% compared to demographic-only targeting.

Hiring for your ICP roles is one of the strongest intent indicators because it shows a company is investing in growth right now.

With Clay, startups uncover two to three times more high-intent prospects by automating signal tracking instead of manually building lists, making it easier to scale outreach without growing the SDR team.

Step 5: How do you capture and qualify website visitors?

Some of your best prospects are already visiting your site, you just don’t know who they are yet. Clay helps uncover those hidden visitors and turn them into qualified leads without spending more on ads.

Start by revealing who’s engaging with your website. You can connect Clay to a visitor-identification tool to match anonymous traffic with LinkedIn profiles. Once those visitors are identified, send the data into your Clay table to enrich and qualify them automatically.

Inside Clay, you can:

• Pull key details such as company, role, and seniority level
• Qualify each visitor against your ICP criteria
• Add enrichment to fill in missing data like email or company size

When a visitor meets your criteria, Clay can generate personalized outreach copy using AI and send that contact straight into your HubSpot sequences or outreach workflows.

This process helps you capture demand that’s already on your site, prioritize the visitors most likely to convert, and turn anonymous traffic into real pipeline, all without increasing your ad spend.

Step 6: How do you find new lookalike companies from your best traffic?

This is the step that turns your existing data into a repeatable growth engine. Once you’ve identified and qualified high-fit website visitors, you can use that data to find entirely new companies that share the same characteristics.

Feed those top-performing visitors into a similarity-matching tool to uncover lookalike companies, businesses that mirror your best traffic in size, industry, and growth behavior. You can refine the search by factors like location, company size, or exclude competitors to keep your list tight and relevant.

Then, back in Clay:

• Import and enrich the lookalike companies with up-to-date firmographic and technographic data
• Find the decision-makers who align with your buyer personas
• Qualify and personalize outreach automatically, then push results into HubSpot or a dedicated outbound campaign for tracking

With Clay’s lookalike automation, startups can scale that cycle instantly. Every closed-won deal can trigger workflows that surface up to 10 new high-fit opportunities for follow-up, turning what already works into a repeatable, self-sustaining system in under an hour.

Step 7: How do you test and improve messaging for lookalikes?

Once you’ve built your list of lookalike prospects, the next step is to make sure your outreach actually resonates. 

With Clay and Octave, you can easily A/B test your outbound messages to see what performs best before scaling. Start by adding a round-robin column in your Clay table to split new leads into two groups, V1 and V2. Each version will trigger a different Octave Agent so you can test variations like:

• Tone or style of messaging
• Prompt structure or writing instruction
• Different AI models or parameters

Once the copy is generated, push both versions into your sequencer and track which version drives higher engagement or reply rates.

The goal is simple: let your outbound learn as fast as your data does. The more you test, the faster you’ll find the voice, tone, and message that converts your lookalike audience into customers.

Startups that personalize outreach based on data from their enrichment workflow see real gains. In fact, personalized outreach in Clay drives 34% higher response rates than generic messaging, because it uses multi-signal and buyer-pain data to make every message feel relevant.

Step 8: How do you activate and measure everything in HubSpot?

All the enrichment and qualification work you’ve done so far comes together through the Clay HubSpot integration, connecting your lookalike engine directly to your CRM so it becomes part of your everyday revenue operations.

Once your tables are ready in Clay, integrate the outputs so every data point automatically syncs with HubSpot. This keeps your process organized, accurate, and ready to act on in real time.

Here’s how to set it up:

• Create rich-text properties in HubSpot for AI research notes, company summaries, or fit scores.
• Automate contact updates and ownership assignments so new leads go to the right reps immediately. Sales reps are 20× more likely to convert a lead when they respond within five minutes of capture, a speed made possible by Clay’s automated qualification and filtering workflows.
• Build dashboards to measure ROI by source, such as which prospects came from your website traffic, Ocean, or Common Room.

When Clay and HubSpot work together, your lookalike prospecting engine becomes measurable, visible, and scalable. Verified, enriched data synced from Clay into HubSpot doesn’t just look cleaner, it performs better. Startups running outbound from verified profiles see 80%+ match rates and fewer bounces, which means higher deliverability, stronger attribution, and more reliable campaign results.

Why this works for startups

Startups grow faster when they learn faster.

This lookalike framework helps you do just that, focus on accounts proven to buy, save time by enriching only qualified leads, and scale by turning every customer win into your next source of growth.

It’s a smarter, data-driven way to grow, built on Clay and powered by HubSpot.

If you’d like to see it in action, RevPartners (an official Clay Studio Partner and Elite HubSpot Solutions Partner) can build the workflow for you for free.

Your next best lead might already be on your site. Let’s help you find them.