How to Improve Custom Bidding Performance in DV360

Hello! I'm having difficulties with my campaigns in DV360, where the average custom value or cost is significantly lower than desired. While I have no issues with Google Ads, improving my impact on DV360 campaigns is challenging. I know what steps to take to optimize search campaigns for better performance, but I'm struggling with custom bidding in DV360. My goal is set at 30, but the actual performance often ranges between 0.1 to 5. How can I enhance this performance to win better impressions? I understand that poor performance is affecting my ability to secure quality impressions. What steps can I take to improve this?