How to choose a marketing agency and what to expect in the first 100 days

Knowing how to choose a marketing agency starts with the right questions: whether it understands your type of sale, what method it uses, who will actually serve you, how it measures results and how it handles your company's numbers and data. The other half of the decision is knowing what happens after you sign. In this post, we bring both together: what to ask before hiring and what to expect in the first 100 days, using how we work at Mtools as the example.

How to choose a marketing agency: what to ask first

The best questions are the ones an agency can only answer well if it has done the work before. Take this list to every conversation and compare the answers side by side:

1. Experience with your type of sale. A long sales cycle, several decision-makers and a high ticket call for different communication. Ask for examples of clients with that profile and what was done for each person on the buying committee.
2. Method. How does the agency start? An answer that jumps straight to posts and ads, with no diagnosis or positioning, is a warning sign.
3. Who actually serves you. Who will be in the meetings, who writes, who runs the media. Meet these people before you sign.
4. How it measures results. Which metrics go into the report and how they connect to leads, opportunities and revenue, not just reach and clicks.
5. How it handles numbers and data. No number from your business should go into a case study without your approval. Under Brazil's General Data Protection Law (LGPD), whoever processes personal data on your company's behalf is a processor and follows your instructions, and similar rules apply in other markets. Ask how the agency handles your leads' data.
6. Who owns the accounts. Ad accounts, analytics and tools should be in your company's name, with the agency as a user.

Warning signs

Be wary of promises made without a diagnosis. Some signs show up in the proposal itself:

• guaranteed results before anyone looks at your data;
• case studies without numbers, or with numbers that have no source or period;
• reports that only show reach, likes and clicks;
• ad accounts created in the agency's name;
• the person who sells the proposal disappears after signing;
• the proposal asks nothing about your sales team.

What your company hands over to the agency

An agency delivers as much as the brief and the access allow. Before day one, prepare:

• brief: products, audience, competitors, goals and what has already been tried;
• access: ad accounts, analytics, Tag Manager, CRM and the automation tool;
• approvers: who approves copy, creative and numbers, and how quickly they respond;
• history: reports, materials and past campaigns, including what did not work.

Also name one person at your company as the point of contact, with time on their calendar for the interviews and approvals at the start, which is the phase that asks the most of the client. A well-built brief saves weeks of back and forth. The templates are in our post on the marketing brief template.

Support material · Templates in PortugueseMarketing briefing packSeven briefing templates, from social media posts to landing pages, for more on-target work from your team or agency.Download the pack

The first 100 days with Mtools

The first 100 days follow an order: understand, decide and only then produce at pace. The sequence of the work:

1. Onboarding. Kick-off, access and a snapshot of what exists. In paid media, we review account settings before touching any ad, as we describe in our paid media audit.
2. Planning 360. Interviews with your team, competitor research and the guide that documents who the brand is, who it talks to and how it communicates. The step-by-step is in our post on 360 marketing planning.
3. First content plan. The month's topics come from the editorial themes defined in Planning 360 and go through your approval. It is the guide's first test: if the plan sounds like your company, Planning 360 did its job.
4. First campaigns. With the positioning decided and measurement checked, campaigns go live and the report starts telling the story.

If you have just started in the role and will lead this change, our post on the first 100 days as a marketing manager helps organize your side.

How to evaluate the agency you chose

Once you know how to choose a marketing agency, you still need to agree on how to evaluate it. Set at the start the metrics that will measure the work and how often you will get reports. We have 12 years on the road, since 2014, and our case studies show what that turns into over time: at Mercafacil, 30% of new revenue in 2025 came from the marketing we do together; at Franq, 40% of acquisition comes from our work; at Orbenk, every video that went viral passed 100,000 organic views.

If your company is choosing or switching agencies, we are happy to talk about where you are before any proposal.

Talk to usWant help planning this at your company?Tell us what you need. We'll reply by email or WhatsApp and, if it makes sense, put together a quote.Contact us

Frequently asked questions

Specialized or generalist agency?

For complex sales, with a long cycle and several decision-makers, experience with that kind of sale matters more than the agency's size. Ask for concrete examples.

How long until I see results?

The start is diagnosis and positioning, and campaigns come after. Agree on metrics for each phase, so you can follow progress before sales results arrive.

What should I bring to the first meeting with an agency?

The brief, last year's numbers you can share, the list of accesses and the name of who approves. The more concrete the starting point, the more useful the proposal.

Is it worth switching agencies mid-year?

It is when the work has no method or clear measurement. Before switching, make sure the accounts and data are in your company's name, so the transition does not lose history.