How to optimise your PMax campaigns

Performance Max (PMax) campaigns from Google Ads offer a fully automated way to run ads across all of Google’s channels. They use machine learning and strong signals to drive as many conversions as possible. To get the most out of PMax, it’s important to pair automation with smart, highly targeted optimisation.

Step 1: Set the right conversion goals

A successful PMax campaign starts with defining clear conversion goals and optimising for them. Be sure to distinguish between primary and secondary goals:

• Primary goals are the actions that drive business success. These might include completed purchases in e-commerce or lead form submissions in B2B settings.
• Secondary goals are useful for tracking and improving campaign performance. These could be newsletter sign-ups or page visits.

Each business is likely to have different priorities when it comes to conversion actions. Retailers should focus on purchases and completed checkouts, as these directly increase revenue. Service providers, on the other hand, should prioritise leads, contact requests or appointment bookings – actions that move potential customers closer to a sale.

Make sure each conversion action is measurable and generates enough data for machine learning to be able to optimise the campaign. Overloading the primary goals with small or irrelevant actions can confuse the AI and slow optimisation. It’s also helpful to assign conversion values to each action to reflect their importance in achieving your campaign goals.

Don’t overlook the New Customer Acquisition goal. In the campaign settings, you can either bid more for new customers or target them exclusively. This approach is ideal if you’re aiming for growth and market expansion instead of re-engaging existing customers.

Step 2: Optimise asset groups

Asset groups are where your campaign’s creatives live. They bundle various ad assets (text, images, logos, videos) into cohesive units. Google uses generative AI to automatically create or modify assets. By providing your landing page URL, you can have Google generate text suggestions and even imagery. This feature saves time but always review the results to ensure brand alignment.

Each asset group should focus on a specific theme, product or target audience. Google will then automatically combine the assets into appropriate ad formats for YouTube, Gmail, Search, or Maps.

Use a variety of SEO-optimised headlines, high-quality images and short videos to cater to different channels. Headlines should be clear and concise, and tailored to the target audience. Use attention-grabbing visuals and ensure videos are short and impactful. Videos are particularly important for reach on YouTube, so don’t skip them – they improve campaign performance across multiple channels.

Step 3: Use audience signals

While PMax campaigns are highly automated, you can still fine-tune performance by providing audience signals. In Google Ads, audience signals help guide the AI in targeting the most relevant audience for your products or services, improving its decision-making. Adding demographics, interests or custom audiences helps the AI focus on the right groups.

Here are some best practices to guide Google without limiting automation:

• Test different signals in separate asset groups: Assign a different audience signal to each asset group. This helps you see which combinations deliver the best results in terms of reach and conversion.
• Use your own data: Upload your customer data—like remarketing lists or Customer Match audiences. These signals are especially strong because they target people who’ve already interacted with your brand, like by signing up or making a purchase.
• Add interest and intent-based segments: Include audiences based on interests, purchase intent or search behaviour to reach users more likely to take action.
• Refresh signals regularly: Review and adjust your audience signals so they align with seasonal trends or new campaign goals.
• Let signals guide the AI without limiting it: Audience signals should steer the AI in the right direction, without restricting how it learns or adapts.
• Stick to specific search themes: Only include search themes that closely match your product or what you offer. Broad or generic terms can reduce performance.

Step 4: Check data feed quality

For online stores, success with PMax starts with a clean, well-structured product feed in Google Merchant Center. This feed holds all the key product details Google needs to display your ads correctly and reach the right users. Make sure your product data is complete, accurate and up to date. Even small issues, liked outdated prices, incorrect availability or vague product descriptions, can hurt ad performance. Use clear, descriptive titles and keyword-rich descriptions to help Google categorise your products correctly.

To take it a step further, consider using Custom Labels. These let you group products by criteria such as margin, seasonality, bestseller status, or campaign priority. Grouping products this way makes it easier to fine-tune your budget and focus on high-value items.

Check your feed regularly to keep your data up to date and accurate. The Diagnostics tool in Merchant Center makes it easy to spot and fix issues before they cause problems. High-quality data ensures your products appear more often, perform better and ultimately drive sales.

Step 5: Refine bidding strategies

Bidding strategies are key to the success of your PMax campaign. With Smart Bidding, Google automatically adjusts your bids to get the best possible results within your budget. That means you no longer need to manually set bids for each keyword or product. The AI makes these decisions based on your campaign goals.

Google offers several Smart Bidding options:

• tROAS (Target Return on Ad Spend): tROAS tells Google to optimise your bids based on the return you want from your ad spend. To do so, it adjusts your CPC bids (cost per click) to reach the target return. Example: If your target ROAS is 400%, Google aims to generate £4 in revenue for every £1 you spend.
• tCPA (Target Cost per Acquisition): tCPA tells Google how much you’re willing to pay, on average, for a conversion – like a purchase or a lead. It then aims to drive as many conversions as possible without going over that target.

If you’re running multiple campaigns at once, allocate budgets strategically. A PMax campaign needs enough budget to learn which combinations perform best, but it shouldn’t pull too much budget away from well-performing Search or Shopping campaigns. Review your results regularly and adjust targets like tROAS or tCPA based on seasonal trends, market shifts or new business goals.

Step 6: Keep optimising and testing

Automation doesn’t mean your PMax campaigns automatically run at their best. You still need to track performance and make regular improvements to get the best results. Keep a close eye on key metrics (KPIs) like conversions (number of completed actions), ROAS (the ratio of revenue to ad spend), impression share (your share of impressions compared to competitors), and cost per conversion.

Google uses your campaign data to refine its approach over time, but you can speed up the process through targeted testing of specific variables. Always roll out changes gradually so you can see what actually moves the needle. Here a few test ideas to get you started:

• Asset tests: Try out different headlines, descriptions, images, or videos. Don’t just tweak them! Make bold changes in tone, messaging, calls to action or visual style to see what resonates with your target audience.
• Audience tests: Compare different audience signals to figure out which groups convert best.
• Offer or pricing tests: Experiment with discounts, bundles or price points to see what drives conversions.
• Landing page tests: Even small updates, like a clearer layout, new product images or a more prominent call-to-action button, can improve the user experience and boost your conversion rate.

After each test, review the results and write down what you learned. Over time, this gives you a solid base for making smarter decisions and running stronger campaigns.

Step 7: Identify and eliminate sources of error

Even automated PMax campaigns can run into issues. Common mistakes that hurt performance include:

• Too little conversion data: If your campaign doesn’t log enough conversions, the AI can’t learn which users are most likely to convert.
• Repetitive assets: If you keep showing the same headlines, images or video, your ads lose impact and variety – the system needs both to optimise performance.
• Outdated or incomplete data feeds: If your product info is wrong or incomplete, your ads might not be displayed properly, or your products may not appear at all.

If your PMax campaign isn’t performing as it should be, take a systematic approach to identify and fix what’s not working. Regular tweaks usually lead to better long-term results than big one-off changes. Track the adjustments you make and assess their impact. Go step-by-step:

1. Check your data setup: First, make sure you’re getting enough conversion data. Then check if your assets are varied and up to date, and your audience signals are on target.
2. Add what’s missing: Give the AI more to work with. Add conversion data, refresh audience signals or include additional products in the campaign.
3. Test asset combinations: Try different headlines, images or videos to boost the relevance and appeal of your ads.
4. Dig into your campaign reports: Look closely at key metrics like conversions, ROAS and impression share. Identify patterns, spot weak points and track what’s improving.
5. Adjust budget and bids: Start with small changes as these often make a bigger difference than large overhauls. The AI also needs time to adapt to new settings.

Why a PMax campaign isn’t a set-it-and-forget-it

Pmax does a lot automatically, but it still needs clear input and smart oversight to perform at its best. That’s because success now depends less on manual bidding and more on giving the AI the right data to work with.

1. Goals: Define clear conversion values and apply new customer rules when they align with your strategy.
2. Assets: Use strong images, videos and ad copy. AI-generated content is fine too.
3. Controls: Set brand exclusions and URL rules to keep your budget on track.
4. Patience: After making changes, give the algorithm 2 to 3 weeks to adjust before making further adjustments.

With the right setup and steady input, PMax can deliver real, measurable results.