When taking pictures with your smartphone, two tips come to mind:
Don’t bother cropping before taking the picture
Almost all smartphones use a digital zoom for zooming instead of an optical zoom. An optical zoom uses lenses to adjust the image being caught by the sensor, but since smartphones do not have the space for optical lenses, they have to do a digital zoom. With a digital zoom, the picture has the same resolution whether you zoomed in or not. What this means is that you can always take the picture without zooming, and cropping it later, and the picture will be the same as if you cropped before taking the picture. Why would you do this? There are many times when you are trying to capture fleeting moments, and if you are spending time trying to zoom, then there is a chance you may miss the picture. More information available here.
No vertical pictures or movies
You’ll almost never need to take a vertical movie. If I have to see another constantly panning movie because it was recording vertically I will scream. Vertical pictures do make sense for some portraits and 1-3 people, but any more than that you’ll probably want to take the picture horizontally.