iOS’ notification system tends to be subtle enough that it can be easy to forget or miss an incoming notification. Fortunately, a free jailbreak tweak called BLightAlert by iOS developer Julio Verne can help mitigate this problem.
BLightAlert leverages your handset’s display backlight to grab your attention for incoming notifications. Once installed, the display brightness changes rapidly from low to high for a couple of seconds whenever an incoming notification rolls in, like so: