FInal product is exactly 1920x1080. Make sure you record wider than that at a 16x9 ratio. Use Background image to the right for proper Ratios (Don't stretch it or modify the ratio).
2
Under 2 minutes
Every Second past that is eating into peoples patience.
3
Create Movement
Zoom in on things (easy on iphone or ipad recordings)
4
Music, Always
Even Cheesy Music keeps it interesting and sticky/memorable