What's a best practice to follow when creating a Performance Max campaign?Limit the number of ad extensions within an asset groupUse the maximum number of text, image, and video assets possibleEstablish conversion tracking after a campaign has been running for two weeksAvoid linking a Google My Business or Google Merchant Center feedNEXT

The best practice to follow when creating a Performance Max campaign is to use the maximum number of text, image, and video assets possible. This allows Google's machine learning algorithms to have a wide variety of options to choose from when optimizing your ads for performance.

It's also important to establish conversion tracking before the campaign starts, not after it has been running for two weeks. This allows you to accurately measure the success of your campaign from the start.

Linking a Google My Business or Google Merchant Center feed can also be beneficial as it can provide additional information that can be used in your ads.

Limiting the number of ad extensions within an asset group is not recommended as ad extensions can improve the performance of your ads by providing additional information and options for potential customers.