How should you approach creative effectiveness in order to boost performance of video campaigns? 

• Use research-backed creative guidelines and iterate with experimentation. 
• Start with all-new video ad creative that's already working well for other platforms. 
• Continue running campaigns with existing creative and slowly introduce new variations. 
• Run an experiment with existing creative and use whichever one performs best. 

Answer: Run an experiment with existing creative and use whichever one performs best.