As has been said, you can check out Taboola’s insights to create high-performing native ads. However, you shouldn’t also dismiss general best practices, such as:

• Use photos rather than illustrations. Photographs have almost 50% higher CTR.
• Denote a benefit. What will happen to users if they click? Will they learn something? Then use the ‘learn’ or ‘discover’ keyword. Will they get a discount? Mention it in the title.
• Stay credible. Try not to offer too provoking headlines but show your customers can trust you.
• Test different creatives at once.