We are slowly, but surely, getting of best pictures on our smartphones, with auto focus, sensors etc..
To improve our pictures taken with a Smartphone, there are different ways:
photo taking app + addition of filter by top to erase imperfections, colors, etc…
using different lenses / zoom
use of a polarizing filter
Here, you can add a new accessory: the led flash lamp!
Yes, Yes, I see you come up with what you're saying to you: "uh… it's use, all smartphones have built-in flash!"
Indeed! That is quite right! But make a photo with the built-in flash and a flash outside, better thought, that doesn't give the same result!
Link: http://www.mobilefun.fr/59215-lumiere-flash-led-loooqs-universelle-pour-smartphones.htm