A Guide to Prompting with LLMs: Buy-Side Edition

This guide is designed specifically for the buy side of the Australian advertising industry — brand marketers, media agencies, and planning teams. It builds on the A Guide to Prompting with LLMs: 2026 Edition, which covers the core framework and foundational techniques. If you haven't read that guide yet, we recommend starting there.

What follows is tailored to your world: developing media strategies, building channel plans, writing briefs, analysing campaign performance, defining audiences, and justifying investment to stakeholders. Each section includes worked example prompts you can adapt and use immediately.

This guide assumes familiarity with the Goal / Context / Source / Expectations framework from the general guide. Every example prompt in this document follows that structure.

The demands on media agencies and brand marketing teams have never been higher. Clients expect faster turnarounds, sharper insights, and stronger accountability for every dollar spent. At the same time, the media landscape is fragmenting — more channels, more data sources, more measurement complexity — while team sizes often stay flat or shrink.

This is where AI prompting becomes a genuine multiplier. It's not about replacing the judgement of experienced planners or strategists — it's about accelerating the work that surrounds that judgement. A well-prompted LLM can help a strategist draft a media plan framework in minutes rather than hours, help an analyst turn raw performance data into a client-ready narrative, or help a planner pressure-test a channel mix against industry benchmarks.

Where prompting creates the most value on the buy side:

• Strategic speed: Moving from brief to draft plan faster, leaving more time for refinement and client collaboration.
• Data-to-insight translation: Turning raw numbers — campaign reports, audience data, market research — into compelling narratives and recommendations.
• Brief quality: Writing tighter, more effective briefs that set campaigns up for success from the start.
• Cross-channel thinking: Quickly comparing channels, benchmarks, and allocation scenarios to build smarter plans.
• Stakeholder communication: Producing clear, well-structured documents that justify investment to CMOs, procurement, and finance teams.

The buy-side teams that build strong prompting habits today will plan faster, think more strategically, and deliver stronger results for their clients.

The general guide introduces a four-part framework for structuring every prompt: Goal, Context, Source, and Expectations. Here's how that framework applies specifically to buy-side workflows.

High-Impact Use Cases for the Buy Side

The following use cases represent the areas where AI prompting can deliver the most immediate value for clients and agencies. Each includes a realistic scenario, a worked example prompt, and a description of what a strong output looks like.

Media Strategy & Channel Planning

You've received a brief from a client launching a new product. The target audience, budget, and objectives are defined, but you need to build a channel plan that allocates spend effectively and tells a clear strategic story about why each channel is in the mix.

Audience Definition & Segmentation

Your planning team needs to move beyond basic demographics and develop richer audience segments that reflect real behaviours and motivations. The client brief says "young families" but you need to turn that into actionable segments with media implications.

Brief Writing & Refinement

You're writing a media brief for a complex campaign that spans multiple channels and objectives. You need to ensure the brief is tight enough to guide partners effectively but comprehensive enough to capture the client's ambitions.

Campaign Performance Analysis

A campaign has just wrapped and you need to analyse the results across multiple channels, identify what worked, and build a narrative for the client that goes beyond "here are the numbers" to "here's what we learned and what we'd do differently."

Investment Justification & Stakeholder Communication

The CMO has asked for a clear explanation of why the recommended media plan allocates 35% of budget to BVOD when the previous campaign was primarily social-led. You need to build a persuasive case backed by evidence.

Competitive & Market Analysis

Your client is entering a new category and wants to understand how competitors are investing in media before finalising their own strategy. You need to pull together a competitive landscape overview quickly.

Advanced Techniques & Recommended Practices for the Buy Side

The general guide covers advanced prompting techniques in detail. Here's how to apply the most relevant ones specifically to buy-side workflows.

Build a Buy-Side Prompt Library

The most effective agency teams don't start from scratch every time. Build a shared prompt library organised by workflow stage — planning, briefing, activation, reporting, and client communication. Store your best-performing prompts and iterate on them. This ensures consistency across the team, speeds up onboarding of new planners, and builds institutional knowledge.

Suggested categories for a buy-side prompt library:

Getting Started

You don't need to overhaul your workflow to start seeing value from AI prompting. Here's a practical path to building the habit:

1. Today
   Try it right now. Every example prompt in this guide is ready to use. Start by running each one of them as they are into your LLM of choice. Then ask the model to turn the output into a slide deck or a PDF. The point is to feel what AI produces. The rest of this program will make immediate sense.
2. Week 1
   Pick one use case. Choose the use case from this guide that matches your most frequent task — whether that's writing media plans, analysing performance data, or drafting briefs. Adapt the example prompt to a real client brief and compare the output to what you'd normally produce.
3. Week 2
   Refine and iterate. Take the output from Week 1 and improve it. Adjust the prompt, add more context, try specifying the format differently. Save the version that works best.
4. Week 3
   Share and scale. Share your best prompt with a colleague and ask them to try it on a different client. Collect feedback. Start a shared prompt library for the team.
5. Week 4
   Add a second use case. Now that you've built the muscle on one use case, pick a second. Layer in an advanced technique like Chain-of-Thought or Few-Shot. Keep iterating.

For foundational prompting techniques, see A Guide to Prompting with LLMs: 2026 Edition on the IAB Australia AI Hub.