What is the most important part of a video’s first 30 seconds?

[BrendaVance]

Retaining viewers past the hook is the hardest part of YouTube. Do you jump straight into the topic, or use a quick teaser trailer at the start?

 

[eHarper]

a very quick teaser or like a cold open can keep the interest of the viewer but it should be very brief. Like in marketing always try to capture their attention first, then you can create interest by jumping into the topic. People's attention spans are very short nowadays so if you take to long to get to your main point or don't explain why they should stay until the end, they are going to definitely jump to the next vid.