What is a recommended best practice for setting up Amazon DSP campaigns to improve performance?

The selected answer Run cross-device campaigns by setting up separate line items for each device type is correct because running cross-device campaigns and setting up separate line items for each device type is a recommended best practice for optimizing campaign performance. By creating separate line items for different devices (such as desktop, mobile, and tablet), advertisers can tailor their bids, creatives, and targeting strategies to the specific behaviors and engagement patterns of users on each device. This approach ensures that ads are optimized for the device on which they are being viewed, leading to better performance and more efficient use of the campaign budget. It allows advertisers to track and manage performance by device type, improving their ability to make data-driven adjustments to maximize return on investment.