Former Android users may miss the LED alerts that let them know a
call or text is coming in. The iPhone 5 doesn’t add a notification LED,
but it is possible to
use the camera flash as an improvised notification alert.

Use the iPhone 5 flash as an LED alert for calls and texts.
Tap on
Settings -> General -> Accessibility -> LED Flash for Alerts -> On to enable this feature.
A word of warning, it is bright and may not fit in with your sleeping
habits or in a meeting, but in loud environments it’s the best way to
see a call or text on the iPhone.